Commenting on blogs can also increase your website's page ranking. Here are some tips which I learned from other experienced bloggers in the Internet
1. Find a blog that has a content related to your site.
When you do blog commenting, make sure that your post is related to the content of your website. By doing this, people won't get confused because they will be directed to a related site.
2. Choose a blog that accepts links to another site.
There are blogs that do not allow you to post link to your site. In order to increase your page ranking, make sure that you comment on blogs that allow links to your site.