There really aren't without paying ... Just keep writing good, quality content that people are naturally going to want to write about and blog about. Make connections in your industry by forming partnerships with bloggers who complement what your forum is about. That's the best way to get your name out there.
cscgal
The Queen of DaniWeb
19,421 posts since Feb 2002
Reputation Points: 1,474
Solved Threads: 229
Promoting a forum may require time and effort but it is worth it. I have created and promoted forums in the past. My lessons learned are:
1. Content - you need to constantly create content and keep the content fresh and valuable.
2. Invite other bloggers or other people you think may benefit from the site.
3. Use social bookmarks. Stumble your site.
4. Promote it on Craigslist.
InsightsDigital
Posting Virtuoso
1,761 posts since Jun 2009
Reputation Points: 68
Solved Threads: 9
There are no. of link directories and forums hubs for making your forum popular. But the main aspect of the popularity is the quality of the content not only posted by you but also by the members. Keep it updated, make it do-follow forum.
shubh09
Junior Poster in Training
52 posts since Jun 2009
Reputation Points: 10
Solved Threads: 0
A lot has been said, and i still have one to add.
Now remember every forum member you get is someone who will possibly add lots and lots of content to your forum, a great reason to be nice to everyone who visits.
red_gal_2005
Junior Poster in Training
93 posts since Jul 2009
Reputation Points: 13
Solved Threads: 0