Its quiet difficult to market forums.You msut have many active members and more posts for better result.
I'm actually jealous of you. You have a decent amount of members and posts. Your daily visitors is outstanding! Look at my forum... with my 30 members. I'm still looking for a way to generate lots of traffic, members and daily posts to my forum. It's very difficult, especially when it's not the only site or project you work on.
One idea is to have general topic at the bottom of your forum. People are not going to a gaming forum for general chat. You have to "sell" the best aspects of your site. Run a contest on this forum for a new header. Yours is a little plain. If I was browsing game forums there is nothing to catch my attention to give me another look. Some other ideas I like on other forums is a featured thread area where you can see thread titles and the start of the thread. I always end up reading enough to make me want to check out the whole thread. Adding a blog is great for search engines and may be a good place to put your featured threads. It takes a lot of work but could be another good traffic source. You and your friends need to participate in other forums. Not just participate but actively market your forum. Whereever possible answer someones question on another forum with a link to your own. If 10 of you do this regularly people will think of your forum as the authority and hopefully increase participation. Hope some of this advice helps
I second your opnion. If OP gives attention to what you have said it will difinitely get his forum to be more popular. You still don't get it. if you don't have good content you may go no-where. I would suggest that do a contest for a good poster. once you get a few of good poster winners, hire them to write more !! I belive this will definitely help your forum.