My favorite tip is to make your blog do follow, add comment luv and keyword luv, like I have on my blog. If you give you will get! Here is a link of an article on how to get more blog comments
You might think that asking a question at the end of a post will help, it sounds logical, but I found otherwise. I found that whenever I leave a question in the post, I get less response than usual. Controversy, on the other hand, works great. Really, all you have to do is post something that people can disagree with, your comments will rocket.