Nothing your doing is wrong. With time and dedication, you will be finding yourself owning a successful community. You need to start out by advertising frequently and constructively. Begin by submitting your advertisement to common promotional sites, even the smaller ones, because every bit of advertising counts. Next, you need to get the word out that your community even exists. Most of the time the problem is that no one knows the forum/site is in existence, when in reality it exist, but lacks exposure. Continue advertising and bumping your threads frequently, and attempt to participate in the endless numbers of other promotional strategies. Packages, post exchanges, member exchanges, affiliation, Ads, Reviews, and providing beneficial reasons to join YOUR community over others.
Ask yourself: What would make me join a community?
Once you answer that question, apply the answer to your forum, and make sure it is provided within the community.
If I had to personally pick from all the other communities to join one and solely contribute, I would probably participate in a laid back, fun and entertaining one. I know those answers are extremely general, but it is true. Most people want to be entertained and feel appreciated for being apart of the community, and if you give your newcomers just that, you will be in greater likeliness to have a visitor become a regular, active member.
I wish you the best of luck, and hopefully you will see the light at the end of the tunnel. A community is a community, regardless of its size. No matter how big or small your discussion board, it remains a community as long as it is up and running.