Blog regularly. The more you post, the better chance you have to reach a wider variety of readers.
Add the blog to blog search engines. There are dozens of blog search engines out there and more being added everyday. Create a good, concise description for your blog, as well as relevant keywords.
Add the blog to toplists. Put the link to the toplist on your blog: every time someone hits the link, your blog moves up in the ranks.
Write comments on other people's blogs. People are always grateful for a comment. More often than not, they'll click on your link and return the favor.
Comment on people's comments. A blog is meant to be a community. Respond directly to people's comments-either in the comments or in a new blog post. This will engage readers so they'll come back more often.
Post on forums. If you write a niche blog, post answers to questions on forums-be sure to put your blog address in your signature. Don't spam forums-make sure your posts are relevant.
Write to other bloggers suggesting a link trade. Put up a link list of your favorite blogs and let those bloggers know about it. They might just reciprocate.