[setishock]

Content is King. Fresh content keeps people coming back time after time. That's easy to say but a little harder to do. That's where you have to devote time to keep it up.
KISS Keep it simple stupid. Easy to navigate menus make it simple for even non forum savvy users to find what they want to look at or do.
Moderating. This is a slippery slope to step out on. You have to show people you mean business but in a way that doesn't drive them away. A hand on the shoulder and a whisper in the ear, works better than belittling a wayward member in the open. Take it to the PM's.
Be flexible. Listen to your members. In all the suggestions, nagging, and whining, there comes that one really great idea that didn't occur to you.
Running a forum is hard work. But if you really enjoy the subject it's built around then it's a labour of love. Whether it makes it or goes down the drain, is up to you. Keep hammering at it.