Link it up
Twitter isn't some self-contained ecosystem. Indeed, part of its charm is that it can act as a filter (through the people you follow) to all kinds of fascinating web content that you may not otherwise have seen. It's a door that swings both ways, so make sure you put links to your Twitter profile everywhere you can. Link it on your Facebook page, your LinkedIn and Digg profiles, your blog, email signature and anywhere else you have an online presence. The easier it is to find, the more followers you acquire.