There are three special ways to promote yourself or business on twitter. I am going to give you a quick rundown those ways.
The first is the use of hashtags (#). You will want to identify trending or important hashtags that relate to your industry and then tag those in your tweets. Make sure it is engaging and important info so you will get people to follow you permanently.
The second is the what is called the @someonefamous strategy. This is done by getting someone more famous than you to engage in a twitter conversation with you and then having there followers/fans become part of your following/fan base. This is not easy but worth the effort and will pay off greatly if you get that conversation.
The third is to pitch your products or services to journalist. They is not a journalist in todays internet world that does not use twitter. They stay on top of twitter because almost every news story today breaks first on twitter.
Get retweeted by posting items that are interesting, funny, shocking or outrageous. People love to share these type of things and will retweet your tweet.