WordPress is a good way of starting a blog because it provides all sorts of hooks for other people to find you through. You won’t have much control over the design without paying WordPress extra, however, (which I thought was really lame, and is pretty much the sole reason I won’t use http://wordpress.com) but that could be a good thing. It means you will focus on content, which is, of course, the most important part.
Like gashgai said, it’s probably best to provide some unique content with a focus. Don’t make a design blog or a web trends or technology blog unless you really think that you can do better than the thousands of people out there doing the same thing. That’s a lot of competition. Try to find a smaller, but still interesting niche. What are you interested in? What do you know a lot about? Write about that! Tell your friends. Update frequently, at least until you have a loyal readership. Link to other articles in your entries that are relevant. If your writing is good, people will find you.
Don’t expect it to happen immediately, or even for a long time. Remember that you’re writing a blog for yourself as much as for other people. Even if not a soul visits you weblog for months, you’re still writing which means you’re still getting better at writing which means someday maybe your content will attract someone else to read it.