I haven't lead a gang in a while, but my tip to you is to not try too hard, if you try to seem too good at the start people would just see that and be turned off by it. Most people that create gangs already have a bit of a base, such as a large group of people whom they have played with in the past but I mean, if you can create a base amount of people before trying to go full on that may help you out a bit. Also be sure you have the skill-set to lead a gang, it requires good leadership and communication skills, it also requires you to be able to teach others to be like this. You also need to know the rules and ensure your entire gang follows them as ultimately if they're being idiots it will also fall back on you.
What I am trying to say basically is, don't expect to make a huge gang straight off, make sure you have the skills and if you don't join another gang for a while and gain the skills you need and be ready for the stress of managing all of your gang members.