Reply to othersBecome an expert in your field and provide information that is useful. Potential customers will recognise this and are more likely to do business with you.
Remember you are a real personPost under your real name and the company's. People respond to people rather than faceless companies. It is OK to post about non-business related items but don't get too personal.
Raise questions and highlight issues in your fieldThis will encourage some interaction between you and your community
Tweet on the goYou do not have to be in the office. There are applications that allow you to update your page from your iPhone or Blackberry
Don't promote your business too muchIf you just post links to your site and don't say anything useful, or interesting - it really is just the equivalent of spam. Plus you won't build a community.
Save TimeSet up a Feed from your Twitter Account to automatically update your website.
You will be judged on the company you keep
Be choosy about who you follow and who follows you.
Consider Multiple FeedsWhy stick to one Twitter Account. If you have a business with different niches then create a community around them.
Make your business easy to followIt is easy to create a 'Follow Me' badge. Add it to your website, business cards and email signatures.
It's behind you
Its very easy to update your Twitter Account background. Why not add a promotion or useful information about your business.