I have a few posts already about twitter
i spent a year recording my twitter activity to find patterns in what twitter users react to, and I have written about twitter management before.
I have found a few more services that are noteworthy so I decided to list them here:
followerwonk is a very good tool, it lets you analyse your followers (and anyone elses followers too) in various ways.
manageflitter is a tool that can scan the people you follow to remove inactive accounts and people who you follow but don’t follow you back,
If you use these tools in conjunction with my previously listed tools then you can gain an insight into your audience and hopefully you can use that info to gain more exposure.