I built a following by commenting on hubs I enjoyed reading, answering questions, and sometimes going to forums. It takes time. I like a quality follower more than a quantity follower and by that I mean someone who is going to actually take the time to read and comment on my work than just to skim through it. In the long run, I think it's better not to comment on hubs unless you have something valuable, insightful, or encouraging to contribute. You don't have to agree always, but disagree respectfully. And whatever you do, don't ask someone to follow you just because you follow them. I don't always enjoy everyone else's hubs and there's nothing wrong with that and I don't expect people I follow to enjoy my hubs. It's a learn as you go process but it's best to be honest in the long run than to feel like you have to do things to please people and boost numbers.