Basically these are the options available to you:
1. Start a crew yourself using the regulations carmi said.
2. Join a crew.
Now if you want to pikc option 2 here's what you need to know:
The Femme Fatales are cool, but if you have a penis you cannot join.
The L.O.D are cool, & only respected members of the board are allowed to join.
The Billionaire Boys Club are cool, & if you want to talk business, join them.
The Immortal Souljaz are cool, but are a bit small-time (sorry Saaphir)
The Rizzlian Order aka The Rizzlian Gimps, are for worshippers of Rizzle. Join them & you'll have to partake in bullshit.
The Goodfellas aka the Gayfellows, are also involved in small-time beefing & all sorts of bullshit.
P.O.W is the crew of Diaz & KAMIKAZI - you figure the rest out.