IMO, getting an FC started is the hardest part.

For starters, you need a goal, something to offer and a reason why people should/would want to join your FC over others. Casual/hardcore is a good start, but there's plenty of FCs with those tags already- you want a bit more. For example, my FC is 'casual' but we expand that as 'we're a casual fc that accepts anyone but focuses on newer players, or players who are shy or anxious about getting into endgame, and we progress at our own pace'


Once you know your goal, the hard part happens- getting people and keeping them. Recruiting people isn't really hard, but unless you have a few good, active people already in the FC at various times of day, its likely people will join, see how quiet it is, and leave. If you have a few people around that can be sure to talk to new members and make them want to stay, thats a big hurdle out of the way.

You should also come up with rules early on, to avoid drama later, and enforce them. If someone's doing something 'wrong' it's much easier to tell them to stop or leave if you already have a rule in place, rather than making it up as things happen and potentially have people accuse you or others of picking on them.

It's also pretty handy to make a LS and invite friends from different FCs into it to help get events going. My own FC uses an LS to chat all the time, because we allied ourselves with another FC (and have other friends from various other FCs in there as well) and never use FC chat. In the early days when we didn't have enough people to form our own regular events, having that LS really helped, and it's continued to make both of our FCs active and fun places.