For starters, you need to have your own blog hosted on your own domain. If you want to make an impact, you need to be able to tell everyone you at least care enough about your business to get your own domain and hosting. Anything else just signals laziness.
Next, you need to frequent to blogs you respect, or would like to be like. Study these blogs and see how the owner is using his blog. Also, try to develop a relationship by offering good quality comments about this topic or blog post.
Once they answer your comments, they will get to know you a bit. This will be good in the long run, because it builds some credibility with these guys. They will be more likely to tell their readers about your blog.
One other way to use the blog is like I do: My own personal resource.
Anytime, you figure out the steps to do something, put them on your blog. This allows you to know the exact steps you took to do something. It has saved me a ton of time by not having to look for it again. And, I also know it has helped others, because when viewing my traffic reports, I can see the pages they are visiting.
There are also blogging conventions monthly. If you can get some time off, then meeting these guys in person is an excellent way to build a relationship. Once they can put a name to a face, they will also be more likely to give you some publicity the next time yo umight need some.
There are so many different ways to get your blog more popular. The one I listed above would be a good place to start. And remember, it is all about building a relationship.