Try to maintain originality, instead of leeching content off of some other site and posting them in your forum, make things unique.
Even though I have changed sides and not supporting warez like I used to, but, you can try all other SEO methods, Google for some and you shall be get some basic steps to follow up.
Do some social network promotions, as the people there are mostly real humans, instead of bots and if they like your site, then maybe your bounce rate will also go down.
Google was not MADE to support warez/illegal sites, so don't get much disheartened when they drop you, coz it is very tough to maintain a steady traffic
All over, try to be some one in the internet, not just a some thing
to a very low amount
