I haven't figured out the secret. I see some blogs that are really poorly written with oftentimes basic to clumsy points thrown in...and they will have 25 comments saying
"Wow...great post!"
Then I will read a moving and insightful post and it will have 4 comments.
I just try to let it go when it starts to eat at me. And I try to always, always, always leave a comment. And I try to respond to a comment by going to the site and commenting on their latest, or something that is interesting.