Thus, I searched around for more tips, how community forums can e more active.
• Have a contest where members can win forum privileges, such as a custom member title, etc., or actual items
• Pay a few people to do a certain amount of posts to get your website active
• You can do some post exchanges with other webmasters, that’s a good way to get your forums going without spending extra money that you don’t need to spend.
• Post around at forums and notify people that your forums are up
• You can exchange links with another forum in the same general field as yours. You need to be careful, as you don’t want to do a link exchange with a website just like yours. If you do that with a bigger website then yours, you might lose more members then you will gain.
• Make an introduction forum so your members feel welcomed
And here are some ways to keep your members:
• Give out custom member titles like: Top Poster, Most Improved, etc.
• Stay active on your own forums, never stop posting!
• Keep adding new things to your forums so your members stay interested.
• Create a section where members can give comments and critique your forum. It’s a great way to feedback from the members of what you need to improve
• Make sure your forums have a set of guidelines that members have to follow. That helps your members not get out of hand
The above source is taken here --> How to build an active community