My forum is www.elitemusclez.com, it is about all aspects of bodybuilding,It is about 5 days old, I have been writing content, approached other forums of a similar nature and also offered a free underarmour package giveaway but cant seem to get any members. I have also installed VbSEO. Can someone offer me some advice???
Facebook ads or google adwords can help you get targeted signups. I had a look at your forum and it could do with having more content too which would entice potential visitors to sign up.
You did a good first step! I think you should work more on your design and add more categories there! Then, you should ask your friends to join and make some posts! I also have a great way to get members and posts...it's free, it works great and I'm also using it (I am also the forum owner)! Please PM me if you are interested!
You just need to keep promoting your website, you need to have content on your site which is going to make people want to sign up, useful people to answer questions helps as well. Keep with link building and article marketing to bring in more traffic and generally, just keep working on your site.