I recently wrote an article on this, but I can't post linkypoos just yet. Once my 7 days are up I'll put up a link to it. I know I could just give the URL, but I really don't want to try and bypass the rules.
I think the best thing you can do is to use video adn social bookmarking to promote your forum and also do some soft permision based marketing. I mean join similar forums and contribute good post and help out then all you have to do is drop a link in your sig ( this is not a fast processs ) but over time this and the social stuff will help you a lot. Dont just stop at a few vid sites and forums just make it your business to do a little each day. Another thing is to boost moral and one way to do that is to offer contests as mentiond to get activity + get some moderators ( find guys you know that have contributed good on other boards with a similar niche ) ask them if they would be interested in helping you moderate the new board if they say yeah then they become help and a valuable asset.
Forums are hard to promote, unless your forum have something unique from other bigger forums that are on the same topic as yours. Just my opinion.
The best way to promote a forum is to join another forum with a similar niche to your forum and use links to your forum in that forum's signature. Just be an active member on the forums of your competitors and contribute useful information and post quality posts every once in a while. Don't spam the forums and have the link to your forum in your signature... You'll be given a bad reputation and people wouldn't be interested in joining a forum if an administrator of a forum has a bad reputation on similar forums.
First, create some informative discussions. Then, market it with some links to not the forum home page, but to the hot discussion thread itself. In the first phase, also allow peoples to post without registration (with an captcha of course).
forum theme directory submission, your theme related forum posting, and social networking can help you for promote your site.
Post a few articles about your forumn on the top social bookmarking sites. Also, do a Google search to find other sites about IT that you can post comments and add your sig block to get people to check out your site. Here is an example of your search string: “leave a comment†IT related or “leave a reply†IT related you will get a listing of IT related blogs or sites that allow you to leave a comment or leave a reply.