On HubPages, people tend to appreciate honest , thoughtful input - and sometimes they'll return the favor. What I've found is that posting very insightful comments on someone's hub will often result in them first responding, and then following you - if you continue to be interesting, that is.
Answering someone's question - and especially with an entire hub, has sometimes resulted in people following me as well.
Finally, when you write several persuasive, informative, and/or useful hubs in a relatively short time, this will get you followers because people will want to see more of your future work.
Hope this helps a bit...