Whoa! More reading material to digest in detail.
How...Off the top of my head...(Obviously requires more breakdown into strategies/methods):
1) Forming your own gang - Starts with family and others you trust, needs clearly defined roles leveraging recognized abilities not wishes/wants.
2) Allowing it to safely increase in membership - Yeah, this one could be tough, good vetting, multiple interviews, common agreement but I myself would want veto power.
3) Building trust and camaraderie in members - actions match words, common sense...goes a long way.
4) Detecting betrayal and problem makers early , and disposing of them without creating divided loyalties - Put me in charge of security, I am usually pretty good at sizing people up and have no problem with disposals.
5) Managing outside perceptions of the group such that others see strength, but not threat. - Outside, who? Do I care about them? If not in my group, they are either running a similar group but perhaps not running it in a manner I deem worthy of trust but perhaps there can be some wary trading and cooperating with them...or I want not a damn thing to do with them in which case what they think of me and mine I don't care about, as long as they know not to dick with me and mine.
6) Using your groups co-operation to disrupt other organizations and groups as they are forming - a kill them before they kill you or a infiltrate them first and then kill them scenario?
I know I know...I gotta read the stuff. I'll get there.