Training

All skills in Rimworld improve simply while they are used; there is nothing special that needs to be done in addition to that. If a colonist is assigned to a task (via the Work tab) with a sufficiently high priority, they will eventually perform it and gain skill points.

In a few cases it is not obvious that a specific task trains a seemingly unrelated ability:

Making smokeleaf joints requires and trains cooking (not crafting).
Making medicine and hard drugs (flake, yayo, etc.) requires and trains intellectual (not crafting).
Cutting stone blocks does not train any skill (but requires crafting to be allowed as a task).
Making Kibble is done at the butchering table, but requires and trains cooking.
Butchering a dead animal is a cooking activity.
Brewing beer is a cooking task (not crafting, which would be plausible)
Many construction tasks could plausibly instead be crafting, smithing or tailoring tasks.
Smithing and tailoring are actually sub-skills of crafting, but do not have their own skill level.

This article talks about a few special ways to forcibly train colonists in certain skills. This is usually only necessary and recommended if you need a certain ability on a colonist, but do not want to use this person for productive work. Normally this is because an untrained worker would be a liability – for example, an untrained cook can cause food poisoning, and an untrained miner can waste valuable resources while trying to extract them.

If you train a colonist by letting them do busy work, or monkey business, you are wasting one of the most valuable colony resources, namely work hours. Only do that if you really have to.

Even a colonist that is bad at everything, and passionate for nothing (these exist...) should be a hauler and cleaner, or maybe the guy who fulfills that caravan trade request 5 days away, before you let them repair a mountain stone face for days just to get them 3 levels of construction.

Using temporary zone restrictions to direct colonists

A technique that is mentioned a few times in this article, is to create a zone only to restrict a colonist to a very specific area, in order to force them to perform a task.

As an example, consider colonist "Molly", who you want to smooth the floor in your freezer in the next few days, and do nothing else. In this case, you will create a new zone for Molly, containing exactly these areas in your base:

the area where the work needs to happen (freezer in this example)
Molly's bedroom (so she can go to rest as usual)
the recreation area and dining table
a place where food is stored (maybe not necessary in this example, because the freezer is already covered)

These areas do not have to be adjacent (connected). The zone can be composed of several disconnected areas.

Now you restrict Molly to this newly created zone. She can now still move between those areas, but in order to perform a task, she needs to be inside one of them, that is, inside the zone. This means she will not use any skills outside the temporary zone, and you will not need to manipulate her work tab to keep her from doing anything but smooth the freezer floor.

This is a very effective method, not just for training, but for prioritizing important work in general.

Combat training

If you feel you are not prepared for the next raid, you can train a few combat abilities. This will always need to be done manually, ie. with the trainee drafted (except for hunting). That means you can not manage the colony in the mean time, and it can be difficult to train more than one colonist at a time. This probably means a net loss of productivity in your colony, so only do it if you feel it is really necessary.

Shooting

The best way to train shooting is to assign the colonist to the "hunting" task. Giving them a long-range weapon, for example a bolt-action rifle makes hunting safer, because animals are less likely to enrage and retaliate if shot at from long range. To be safe, only hunt passive animals that will never retaliate.

Deliberately damaging your own structures or buildings does not improve your shooting skill.

Giving a really bad shooter a weapon not suited for the task, such as a machine pistol of "awful" quality, means that they will possibly hunt for a long time before actually killing the animal. Do not expect a colonist that you train this way to be very productive for the colony.

Aggravating animals

Outside of hunting, some resilient animals such as the Megasloth, Rhinoceros and Thrumbo can give a lot of shooting skill by kiting them, and slowly shooting them to death with a low DPS weapon. You need to be very careful with this approach, because those animals do a lot of damage if given the chance to get into your melee range.

This is a special case of deliberately slow "hunting".

The best weapon types for this tactic are weapons with a fast windup and high shot frequency, not too short a range, and low damage. This makes you use the skill more often, by firing more shots, and has your "training dummy" last longer from low damage.

This approach does require extensive micromanagement, and you won't be able to perform other manual tasks in the colony in the meantime. It is even possible that actually killing the animal will take so long that your colonist will pass out from exhaustion or go into starvation. You must have a capable shooter available to finish off the animal and end the training if necessary.

Melee

Fighting anything with melee attacks will increase the melee skill. Hunting with melee attacks works, but animals are prone to fighting back so be warned (this is true even for animals that never retaliate when hunted from range). You will have to draft the colonist and "hunt" the animal manually by attacking it. An undrafted colonist will not hunt if they are lacking a ranged weapon.

If you want to train a character this way, use the best possible armor so they will take less damage from the animal. Taking no damage at all is usually not possible, so do not train a colonist that you require to be in good shape; they will at least have a few bruises for a couple of days, reducing their manipulation skills and movement ability. Also be aware that attacking herd animals (like muffalos and wild boars) can enrage the entire herd, usually leading to a heavily injured colonist, or worse.

Tamed animals will fight back, so they are not safe training dummies; they can however be kept in a controlled environment which makes them more convenient targets. There is also no risk of an entire herd taking revenge for you hurting their friend. You can patch up the animal you just abused afterwards, which will train the medical skill.

Using melee attacks does raise the skill very quickly, and you will hit the "soft" XP cap of 4000 points in a matter of a few attacks. Disengage afterwards, because training over the soft cap is not efficient.

To level melee more safely, take prisoners who are incapable of "Violent" and repeatedly punch, then heal them in their prison cell. To avoid accidentally killing your prisoners, use fists only with neither a melee nor ranged weapon equipped. Carefully watch the health of the prisoner pausing the game between each punch if needed. A colonist with no weapon (not even a ranged weapon) does up to 7 base blunt damage per punch (see Base Melee Stats for details), so when any single body part falls below 8 hp remaining, stop and allow the prisoner to heal. This will allow you to train medical skill as well.

Construction

Construction is already trained quite efficiently by simply using the skill, since construction is such a common activity in an expanding colony.

Smoothing walls and floors counts as construction, is very time consuming, and does have no quality penalty associated with it. It is maybe the best way to train a low skilled worker, without the risk of wasting materials or creating bad products. Having your apprentices do the smoothing keeps the master constructors free for more demanding work. Restrict the trainee colonists to the respective areas by creating a temporary zone, and let them do wall and floor smoothing exclusively for a while.

Making furniture is not the best way to train construction, because colonists with low skill will produce low quality furniture, which has then to be deconstructed and re-built, wasting material in the process. You can, however, keep deconstructing and reconstructing the furniture until the desired quality level is produced, if you do not mind losing some resources along the way; the popular mod Quality Builder helps tremendously.

If you are about to build a lot of walls in the colony, you can temporarily take your capable builders off the construction task, and let only your trainees build the walls and roofs. Walls do not have a quality stat, so it is not possible to create bad products. The apprentices will take a little longer, and probably "botch" construction several times, but the end result will be the same.

Do not train construction when high value material is involved, such as cloth (for carpets) or components (when making things like power generators). If the colonist "botches" construction in these cases, a fair amount of material will be irretrievably wasted; only do this if you have plenty of surplus so it would not matter.

Repairing things to learn construction

Only do this with a colonist that really needs to be up to speed in construction now, if you have absolutely no other suitable construction work to do at the moment. Repairing structures just for training is probably the worst kind of monkey business you could give to your colonists, and a horrible waste of work hours.

You can damage structures, usually purpose-built stone walls, deliberately by damaging them with melee attacks, shots or grenade blasts, and then have your construction builders repair them.

This will not train shooting skill. Use the shooters only to damage the structure, then undraft them and have them resume their regular colony duties. Of course the shooters could be the very same people who will do the repair work just after. Shooting skill does not matter much in this case, as pretty much everybody is able to hit a wall from point blank range...

By far the best approach is to smooth any stone wall, damage it, and repair it. Smoothed walls count as constructed walls, so they can be repaired. A smoothed granite wall does have 900 hitpoints, almost as much as a plasteel wall. Smoothing the wall will be training construction as well, hitting two birds with a single stone.
Designate the colonists you intend to train so that they can only repair. Create a zone around the training area, and the general facilities of the base, then restrict the trainees to this zone.
Skill training becomes much less effective after 4000 XP has been acquired in a skill during a day. Take the trainees off the training task by removing their zone restriction after the XP cap has been reached for the day.

Mining

Unskilled miners will let resources go to waste if they mine an ore vein. You can check a colonists mining yield stat to see if they are already at 100%. If they're not, do not use them to extract valuable resources from a mountain.

To train these people, restrict them to a temporary zone with a mining job in it that does not include any valuable ores (even steel will become valuable eventually, make no mistake...). If you dig into a mountain face randomly, be aware that this could become a space for infestations to spawn if the location is too close to your colony.

If you have developed deep drilling already, you can let your apprentice miners work the drills. Waste of resources is usually not a problem anymore at this point.

Cooking

The cooking skill level is increased by butchering, cooking meals at a stove or campfire, and also by making smokeleaf joints. If an unskilled cook prepares meals, they carry an increased risk of food poisoning. This is a fairly disrupting condition that should be avoided, so it is not optimal to train a new cook by letting them prepare meals.

Making smokeleaf joints

If a colonist has low skill but high passion for cooking, you should train them as an additional cook. The downside is that meals prepared by this character, while he or she is still learning, carry a high chance of food poisoning.

Cooks can, however, also be trained by having them make smokeleaf joints out of leaves at a drug lab. This will train cooking just as fast as preparing meals, without the risk of making anybody sick.

Set up a dedicated work bill at the drug lab, and restrict it to the character that you would like to train in cooking. The character needs to have priority to "Craft" things on the work tab. Make sure the drug lab is not occupied by other tasks; the easiest way is to put the smokeleaf job in the first slot on the list of bills.

This strategy requires drug production to be researched, and to grow or buy smokeleaf leaves. The latter is, of course, a way to train the plants skill (sowing smokeleaf only requires 4 plants skill). Smokeleaf products have good recreational and cash (trade) value.

Training cooks with smokeleaf is an excellent strategy.

Plants (growing)

Letting an unskilled grower harvest your fields will waste some of the product; check the harvest yield stat of the colonist. If you need to avoid this, you will have to create a – possibly large – restriction zone to keep this colonist out of the area that they must not harvest. Allow them areas where sowing needs to happen.

Chopping trees is a good way to train plants. Disallow the task ("plant cut" in the work tab) for your skilled growers, so your trainees will get more opportunities to chop wood.

If you are growing plants that only skilled workers can sow (like Devilstrand and Healroot), make sure that your trainees will sow all the other fields. Do not let your skilled growers take that work away from them. Again, you will probably need to use restriction zones or work tab micromanagement to facilitate this.

The Work Tab addon by Fluffy makes partitioning the growing tasks a lot easier, avoiding the use of temporary zone restrictions.

Crafting

The only way to practice crafting is to make things, either at a crafting spot, tailoring bench or smithy. Fabrication benches are only usable by already skilled crafters. Drug production and brewing does not train crafting.

If you have no good crafters yet, you will produce many items of "poor" or "awful" quality. It is not possible to retrieve raw materials from crafted items (unlike constructed items) – after you have crafted an item, you have to either use it or sell it as it is. This means you should not use any valuable materials, such as Thrumbofur, Megasloth wool, Hyperweave or Plasteel to practice crafting. Only let your most competent people handle these super-valuable materials.

Weapons are not a good item class to practice crafting, because they only sell for 60% of market value. This is good for game balance, because a lot of weapons are dropped during raids, but it means that you cannot craft weapons and hope to make good money that way (not even if you happen to produce a good quality item).

This leaves armor items and clothing: armor requires valuable ingredients, so usually crafting is practiced making clothes.

Crafted items get a market value that is composed of

the work invested into making the item
the value of the raw materials used
the quality of the item

The market value multiplier for "awful" items is 50%, for "poor" items it is 75%. In those cases it would have been better to sell the raw materials instead of the item! To cut your inevitable losses, only use the cheapest material you can find if you expect to produce a lot of bad quality stuff. Good candidates are birdskin, pigskin, lightleather, patchleather and plainleather. In particular, do not use cloth (needs to be bought or grown) or human leather (too expensive).

To further limit your losses, you can slow down the work deliberately, by crafting under poor conditions (outside, in the dark, not using electricity, in the cold, ...). Skill experience is granted over time and not by work units. Crafting as slowly as possible means you will waste less material in the same time span.

If you have a competent crafter (level 8 or higher) that you want to train further, one good way is to let them make advanced components at a fabrication bench. You will need a lot more advanced components to build the space ship than you can usually buy from traders, so making them early is never a waste of effort. They do not have a quality rating, as long as your crafter can make them you will get full value. Likewise, bionic limbs and organs can be made by anyone who meets the skill requirement, but it is difficult to know in advance which ones you will need.

Artistic

There is not much to be said about training artistic crafting; just have your aspiring artist craft as many sculptures as possible.

"Awful" sculptures have a negative beauty value, so they actually make the environment more ugly. Great to put into the bedrooms of ascetic colonists, but should be deconstructed otherwise.

Use the material that you can spare the most of; wood is often a good choice. Jade has the best balance of beauty and availability, so it should be reserved for more capable, possibly inspired artists.

Medical

There is something that a typical Rimworld campaign never lacks: work for your doctors and surgeons. It is still possible to get some extra training.

Performing any type of surgery is staggeringly efficient for training medical. There are several opportunities for cheese tactics in this area:

Repeated, but pointless, surgery such as adding and removing peg legs or dentures; even if the customer was entirely healthy to begin with, these procedures are not counted under "organ harvesting", so nobody in your colony will mind, not even the "patient". It will leave the patient mangled, so it should only be done with colonists about to die, or with prisoners or guests that you plan to release shortly.
Organ harvesting. This can be done three times per customer, eg. by taking a kidney, half a lung and a heart. It is strongly frowned upon by most colonists.
Euthanize animals instead of slaughtering them; can be cheaply done with herbal medicine. This has no downsides, and even if the procedure "fails", no harm has been done.

The XP granted by a surgical procedure depends on its duration. For reference: at 100% medical operation speed and Interested passion, 2,000 XP are granted from performing a leg replacement. Shorter procedures will award less. Your mileage will vary.

Note: because performing surgery gives so much XP, a single colonist will hit the soft learning cap of 4,000 XP per day rather quickly. Spread out the procedures over multiple doctors and days.

Social

Each social chat with a colonist gives 4 social XP per per speech balloon at Interested passion and neutral mood modifier.

Having a friendly chat with a prisoner in order to convince him or her to join the colony gives roughly 50 social XP at Interested passion, per speech balloon. If you are recruiting prisoners, only assign the "Wardening" work type to the colonists whose social skill you want to improve. The Work Tab mod (or a similar mod) allows more control over the various tasks related to wardening, so it is recommended to make this more viable in normal colony operation.

Setting the prisoner interaction mode to "Reduce resistance" (and not "Recruit") will allow wardens to keep having conversations indefinitely, allowing skill training. However, this costs a lot of food over time to keep the prisoner alive.

Intellectual

Intellectual skill is gained by doing research, and by making hard drugs and medicine. There are no special techniques available to make this more efficient. All research done is equally valuable, and neither medicine nor drugs have a quality rating; this means that who you employ for these jobs only influences how long it takes to finish them.

Animals

The animals skill is very versatile, and can be trained in various ways.

There are two animals related tasks where unskilled colonists can be a liability:

Failed tame attempts may cause the animal to retaliate; this often leads to the animal handler getting injured, a lot of the times while being a fair distance away from the base.
Milking or shearing animals can fail, resulting in all of the product going to waste; this is especially painful when shearing (gathering wool), because wool takes many days to grow back.

Because of this it is best to let unskilled animal handlers only train animals that are already domesticated. If this fails, some food will be wasted, and the animal might lose some training from decay, but nothing worse will happen. Only your qualified animal handlers should be allowed to milk, shear or tame wild animals.

It is very finicky to assign all your animal handlers to the jobs best suited for them. It can be done with a lot of manipulation of temporary zone restrictions, but the recommended way is to install a mod like Work Tab: it allows for fine-grained control of the various animals related sub-tasks.

Guides

Progression: Quickstart Guides • Basics • Intermediate Midgame Guide • Advanced Endgame Guide • Ending the game
Scenarios: Lost Tribe Guide • Rich Explorer Guide • Naked Brutality Guide • The Mechanitor Guide
Survival: Extreme Heat Guide • Extreme Cold Guide • Extreme Desert Guide • Ice Sheet Guide • Sea Ice Guide • Events Guide
Combat: Defense tactics • Offense tactics • Weapon Guide
Construction: Colony Building Guide • Defense structures
Production: Food production • Money making guide
Other: Skill Training • Permadeath save conversion guide •
Ideology Min-Maxing