Here's a simple tip to get more followers organically:

1. Go to your Twitter settings (found by clicking your icon in the top right-hand corner).
2. Select 'Find friends' in the left-hand column
3. Choose your email provider (there are only four choices at the moment).

Twitter will give you the option to follow them all. You don't actually have to do this, and if you do, I'd urge that you manually check them to uncheck problematic people....

Connecting with your email provider, even without following anyone, means that you will now show up on these people's Twitters as Who to follow suggestion. 

Not a bad way to stay at the front of your prospects' minds.

You can read more about it here.