Use precision aiming (click right thumbstick) and aim a gun at a character, and hold it there. After a few seconds, one of three things will happen. 1.) They throw their hands up, face you, and eventually drop some money and run. 2.) They cower in fear or run. 3.) They're a gang member or cop and flip you off or basically brush you off, and with enough time focused on them, will trigger a one whatever wanted level.
Obviously, you want the first one. As for list of homies, check the walkthroughs, there's probably one listing them.
Best time to get the 50 muggings you need to get Jane is after the VERY FIRST tutorial mission (Jailbreak, the one w/ Carlos). Once you finish that mission you'll end up on the docks. So equip your pistol(s), turn around, and start mugging EVERYBODY.
Note that when you begin to mug someone everyone around you will run away but there will always be some dumbass standing around lol. Also note that you don't have to shoot them (you don't have much ammo to start so try not to shoot) and do NOT try to mug the pimps that show up or they will all come and attack you.
Tip: There are places in Stillwater where you'll see loads of people standing around smoking. These are good places to do muggings. I did all my muggings in one session at a place in Factories just after a mission. After I'd mugged a person, I'd run over to another part then run back and more smokers had spawned.
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