You try to make friends on lots of servers, build yourself a tree of friends and one day you ask them if they wanna be staff on your server. The fact that they would be staff would make them the most active ones (especially youngsters). You'll be lucky if you fall on active players.
So, I just wanted a thread so people who have and or are currently running a GMOD Community to let people know what you did right or your tips on starting from scratch with almost no players?