1) Social media has been a great generator of traffic for me, particularly Twitter and to a lesser extent Facebook. I'm also on Pinterest and use my website as well.
2) Participating in forums could be a way for people to get to know you, although I participate based on personal interest. I don't think it's generated any increased traffic.
3) Read as many different hubs as you can (that interest you) and follow those folks. I try to follow hubbers who I think are writing important, relevant material. And then I do everything I can to promote them both on HP and social media. I'm proud to say I helped several new hubbers gain traffic by promoting them as much as I could. To be honest, it's not always reciprocated, but I try not to let that stop me. Good writing is good writing.
Politics (esp. race), recipes and religion generate the most traffic, from what I can tell. I have chosen not to write on those topics too much, so I don't get the traffic that others do.
But good luck. Just write good hubs and the traffic will come.