'Course, three of my four Action agents were recruited from badfic, so I guess there's a probability curve at work somehow. You were referring to Ilraen-Aroline-Fothergill, Gall Bonecrusher, and Derik. For the latter two, links to their recruitment missions and interludes can be found on their wiki pages in the "Recruitment" section under "Mission Logs." Ilraen only has the interlude part, since the mission was never finished, so you'll find that as the first entry under "Mission Logs."

The aforementioned sections are generally good places to look for a given agent's recruitment story, if they have one. If not, their first mission may discuss their recruitment, though the detail will vary. If you're looking at a mysterious character, their origin may not come up until later in the spin-off. For some characters, it may not come up at all.

There doesn't seem to be a list of recruitment stories at this time, so if you want to compile one, that would be cool. The Badfic Characters category might be a good place to start looking. For non-badfic characters, you may find the wiki's search bar helpful, though not all hits are good ones; I just took a peek myself. Otherwise, I guess you'll just have to do a lot of reading, which is no bad thing. I've often been surprised by what I find in places I never would have thought to look.

For general guidelines, that depends a bit on where the recruit is coming from, but basically the procedure is this:

1. Convince person to join. Incentives may include threats (e.g. "your other choice is dying when this fic ceases to exist"), bribery (e.g. "so, you like weapons and hate Sues, huh?"), and outright lies (e.g. most recruitment pamphlets/ads found in World One), though probably not all at once.
2. Provide transport to HQ.
3. If necessary, take them to FicPsych; otherwise proceed to step four.
4. Get them to the Marquis for processing and assignment.
5. Training of some sort may be assigned. If not, proceed to step six.
6. The recruit is assigned to a department and RC. They are now an agent and should go meet their partner.

~Neshomeh

P.S. The wiki is also useful for looking up the proper spelling of agents' names. {= P