Commenting on blogs has NOT been an easy challenge.
1. First you have to read the original posting, and try to understand the point that the blogger tried to make.
2. Then you have to think on what is your own opinion on that particular topic.
3. Then you have to think if you agree or disagree, and how you can express it in a constructive way.
4. You also have to think if you can contribute with something new or different.
5. Finally, try to write as clear and concise as possible, so that any reader can understand it.
I am sure we will get better on this with time and practice.
On the other hand, having followers and readers is very rewarding, because it makes you feel that you are not alone in the cyberspace! :-)