I don't be leave forum posting is the way to go for your linkbuilding, focus on quality strong backlinks (sites that are related to yours). I really be leave its quality over quantity. Let me say this if you have 10 highly relevant links (with pr) you will get more out of it then 100 DP signature links. But that's just my opinion. NB. if traffic is what you are looking for forum posting can be very helpful (almost all visitors to my web directory come from here).
Best methods submissions , either site , article , video etc... forum posting , group posting earns nice traffic , same goes with social bookmarking , gaining backlinks from similar sites via exchanging will increase PR. If you can spend $ then PPC is also one option ... Eventually you should update your site with fresh content in regular intervals....- my 2 cents