When I see a community I always go to the articles and then view how many users are online and the amount of active members then if I think is good looking then I'd sign up.

1. Brilliant content
2. More brilliant content
3. Update the site with more unique content
4. More content
5. Get some friends to sign up, then tell them to tell friends.

Never try contests, they aren't ever very successful, ever! You waste your money and half the time the members who were posting leave immediately after the contest. You waste money on fake posts