How can I build up my forum? I already have the software and a good amount of useful posts. I'm mainly talking about getting new members to sign up and post...
It's a poker forum. I'm not making any money of it, nor am I making it for profit purposes. I just want to build a good community. Therefore I don't wana spend too much out of pocket either. I already bought VBulletin software for it http://www.pokereagles.com/poker-forum/
Check out http://www.itamer.com/getcha-forum-running/323/ and also this thread: http://forums.digitalpoint.com/showthread.php?t=200489
Poker is very hard to start up a forum. I'm running DeuceAce poker forums for over a year and only have 1400 members and over 8000 posts. Normally I would have a lot more but there are that many poker forums and most run by companies with a lot of money backing meaning they can put a lot into marketing and promotion. You also might want to check out my gambling affiliate and webmaster forum.
The answer is simple: find best ways to obtain targetted visitors to your site. You can try Adwords, advertising on related sites with large user base and developing a content site which will support your forum. (you can put an attractive sitewide link to the content site pointing to your forum.)
Go out and socialize if you don't want to spend any for advertising. Visit other poker related sites/forums/hang-outs and try to make people visit your site decently.