Skill farming works by taking advantage of the price difference between skill injectors and extractors. You max out your attributes, train the required 500k SP to extract, then sell the injectors. Rinse and repeat.
The following is boring math that shows how it roughly works out:
Prices based on Perimeter sell/buy split. Extractor: 320M ISK Injector: 760M ISK Difference: +440M ISK 2700 SP / hour -> 1,944,000 SP / month = 3.888 extractions 440M * 3.888 = ~1.7B ISK * 0.95 (taxes) = ~1.6B ISK
Keep in mind that these prices are obviously not fixed and the above was shown just for the sake of an example. The price difference between extractors, injectors, and PLEX is generally high enough for you to barely break even with a single character, and you will rarely be in the red when 2 or 3 characters per account are farms.
All that said, the main purpose of skill farming in this guide is not to get free ISK per month. The purpose of farms to keep your existing accounts PLEXed so you don't relapse into an alpha. For example:
The first character in Perimeter is the primary farm for this account, and he doubles for a market alt. If you want, you can give your skillfarms secondary roles to do other activities and make more ISK or even pay for your main's MPTC. More on this later.
Because he's sustaining omega, the other two characters are also omega for “free”, especially the second account, which is the “main” you can actually undock with and use omega-only ships. He doesn't have to get out of his Muninn, Jackdaw, or whatever. All without opening your wallet or endlessly grinding.
The second skill farm is optional, though it earns a bit more ISK because MPTC's are cheaper than 500 PLEX.
Do keep in mind that while skill farming to sustain omega is substantially cheaper than buying 500 PLEX, that PLEX isn't adding extra skills for you to train. You'd need to buy MPTC's for your main once you can afford it. If you can't, no problem. Just let the MPTC run out while you keep farming.
>5 million SP character with a bonus remap that never undocks and/or is very unlikely to die. How you reach 5 million will be different:
Cybernetics V to use the training implants. This will slow down training for your first 500k and make your first month a bit rough.
2 billion ISK per character, spent on:
Optional, but you may want character tracking software, such as:
If your account created via referral link and was given 1 million SP, do NOT redeem it until you reach the 5m limit.
If you're starting from scratch, how you bring your characters up to 5 million SP isn't terribly important. All that matters is that it's reached in the first place. That said, training the Magic 14 + Cloaking + Clones + Interceptors isn't a bad start.
If you're an alpha and can't train some of the skills to level V, feel free to copy this skill plan: https://pastebin.com/s67imxML. Change the missile/ship skills in the end as you see fit. EVEMon emp file: https://drive.google.com/open?id=1n-bDce4RDEStkaL3ktF0J5SuPr2-X0QD
Like PLEX, MPTC's and skins, extractors can be used remotely. They can even be used from the delivery hangar and be put into your regular hangar. This means your market alt (which is a skill farm) can buy extractors from Perimeter, deliver them to your PI alt in Eso/Delve (which is also a skill farm), have them extract remotely, and contract them back.
This opens up a lot more options, namely:
Though utility alts are good to have even without making them skill farms, these can nonetheless be converted into farms as well.
The best example is market alts. These are typically already in Jita or Perimeter, stay docked 24/7, and have a plethora of skills you can juggle between, like Visibility and Procurement. Like I mentioned before: their usefulness is irrelevant. You're extracting them anyways.
Through remote extraction, you can also turn your indy alts in Eso into farms. Science skills can be used for invention, reaction and reprocessing skills overlap quite well, etc.
Note that if they aren't already trained, many utility roles will have skill requirements that are not aligned with your attributes (see above screenshot). This means that initial training will be slow which eats into your first few month's ISK. For example, Planetology is different from Interplanetary Consolidation. Broker Relations has Willpower as its primary. Just be mindful of what needs what.
When an account is in an alpha state, extractors will only work on omega level skills. If you go AFK and relapse, you won't be able to extract skills and make buying that PLEX a bit easier. In practice, this means prioritize extracting alpha skills first, and train omega stuff only.
EVE-Mogul has a handy tool that tells you how much ISK you can make by skill farming, but you need to make an account to use it. Super annoying, but just use a burner account and it should be fine.
While the main purpose of this guide isn't to gain passive ISK, you can still earn a meaningful amount per month if you min-max your orders and use all 3 toons on an account, as shown here:
Jesus Christ, 1.4 billion, right? Now you know why autists like me own 10 skillfarm accounts. This still means you have to do a shitton of micromanagement like contracting to every. Single. Character. And. Back. Honestly? Just stick with one account. You have more fun that way.
Also, as stated at the beginning of this wiki, prices will change wildly depending on the market's mood.
Note the options on the bottom of the screenshot. See how I'm getting extractors from 10 Packs and not just buy orders? It turns out 1120 PLEX (the price in the eden store for the pack) is cheaper than the prices on the market. Experiment with these a bit. Sometimes MPTC's will be cheaper, maybe you feel like selling to buy orders instead, etc.