Know your audienceThere are several tools available that can help you to gauge reader interest on various topics. For example, you can use HitTail to research topics to write about. HitTail will give you a list of the search terms used by those who visit your blog through a search engine. These search terms list can give you ideas for your future blogs.
Add features like bookmarks, `email this post to a friend,' RSS readers etc. This will increase your visibility as well as help readers to come back. Such tools will promote your blog and increase traffic.
Technorati is one of the most popular search engine for blogs. Use Technorati tags at the end of your blog posts. This will help classify your blog posts by topic and add them to their index.