What are some good ways for me to make more money on Twitter? -

I ve been using sites like SponsoredTweets and Twittad for a while now. Besides these two popular sites are there any other good sites for a established twitterer (21k+ followers) to tweet ads for or stuff of that nature?

I think you lose followers if you try and tweet ads. They will see very quickly you are making money off their readership.