There are different “personalities” when it comes to tweeting. Some, like @guykawaski, post what seems like every few minutes. They share awesome and relevant links they think their audience will appreciate.
There are others who only post their new blog posts or things that are relevant to them. I don’t recommend this – share value and you’ll be a lot more likely to gain a loyal following.
There are some in the middle – they post things important to them, interesting links, links to their posts or products, and so on.
That is more of what I recommend and try to do.
1) Find and post interesting links relevant to your market. I find links using http://alltop.com and news.google.com.
2) Post about your new blog posts
3) Post links to special offers or events
4) Retweet interesting tweets from those you are following
5) Personally reply to people you are following (initiate some conversation!)
If you are looking for more help using Twitter to market your business, check out Twitter 101.