Recently, I've been playing around a lot with my @ConstructiveTra account on Twitter.
There's an awful lot to do with the program, but one of the first things I decided to do was follow a bunch of people who I want to read regularly. Then I started following potential clients and writing content they might be interested in. Some of the clients have followed me back, and I guess that could be the beginning of a good relationship.
After a while people started following me, and I decided I would follow anyone back who followed me, as long as they weren't publishing anything offensive, or totally irrelevant.
After some time I noticed that the number of my followers was falling. Looking into it, I realized that many of the people who followed me did so just to get me to follow them back, now they have stopped following me. Personally I think that tactic really sucks.
There are a few different software solutions, and now I'm very strict about clearing out by non-followers on a regular basis, unless of course, they are regularly producing content I'm interested in.