No 2. Profile
Fill in your bio page. If people know you and something about you, they are more likely to follow you rather than following a stranger with interesting tweets. Bio pages are also featured on the twitter Suggested users page, so if you have a good bio page put up, people are likely to follow you more.
No 1. Good tweets
Maintain good tweets, the really good tweets, on your first page. This will really lure people into following you. If I come across your profile page and I see some dumb links and statuses tweeted, I won’t bother following you.