The most important thing to a good blog is regular contributions. Writing at least three posts a week is going to help you develop your voice. After a few weeks you'll notice your blogs start having a particular style.
Once you write a blog and you're used to how it's done and what your own style is, you'll want to eventually start finding ways to A:) promote it, and B:) engage your readers.
The best way to promote your own blog is to visit other blogs regularly and post intelligent comments; not just "hey, I like your blog" comments, but comments that show you actually read what was said, and you have your own view about it; there's a good chance people will see that comment, click on your name to see who you are and find your Blog (which is listed in your profile).
To engage your reader you simply want to occasionally write blogs that gets response. Ask open ended questions in your blog, or simply say "What does everyone else think about this?" You can also do this by posting controversial material--don't be afraid to talk about politics or religion; just don't do it offensively...unless that's the voice you're going after.