Follow people with the same interest as u and tweet often enough to be worth following , you will slowly build up a following and it does take a little time to get "real people" following you and interacting with you, which in the end is what your looking for. It is a process and doesn't happen right away so like everything else takes a little time and effort.
Just make a nice profile. promote your tweeter page on your blogs, articles, website, Facebook and other social sites.
Use twitter karma, check who is not following you , just unfollow them and try to get new followers. Do this one's a week