You can do it manually or using Scrapebox software. I prefer the second approach.
How to get your comments approved:
- Address the blog owner by name.
- Respond to a previous comment.
- Answer or ask a question regarding the article.
How to find .edu blogs for commenting:
- Search for:
site:.edu inurl:blog "post a comment" - "you must be logged in" -"comments closed"
- Search the Moodle platform:
site:.edu inurl:login "Login here using your username" "For full access to courses you'll need to take a minute to create a new account for"
- Search the Disqus platform:
site:.edu "blog comments powered by Disqus"
All the best,
P.S. ------- Please, share your experience about blog commenting! -------