Here's a pretty good article about using Twitter.
10 Ways Twitter Can Boost Your Social News Profile
Building popularity on Twitter is about gaining followers, and the most fundamental and important concept to learn about building popularity is the idea that when you follow someone, they'll get an email about it and there's a good chance they'll follow you back. If that doesn't work, try responding with an @ to something they said. If they check their "replies" stream, they'll see it and possibly follow you.
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Here's another great video from the folks at ThirtyDayChallenge about setting up a Twitter account.