You might just need more traffic. If you take a look at this story on my blog about sleeping on long flights (http://blog.jgc.org/2010/06/how-to-sleep-on-long-haul-flight...) you'll see that it has 14 comments. A quick look in Google Analytics says that it had 22,994 page views. So one comment per 1,600 page views.

Another blog post, about messing around with an Ikea train set (http://www.jgc.org/blog/2010/01/more-fun-with-toys-ikea-lill...) received 26 comments and has 56,373 pages views. So one comment per 2,200 page views.

One last example about squaring numbers in your head (http://www.jgc.org/blog/2010/03/squaring-two-digit-numbers-i...) has 15 comments and 21,380 page views. One comment every 1,400 page views.

So, more traffic helps. What's the URL of your blog?