Try to make each comment different, stop using duplicate comment for commenting. This is best method for commenting according to me.
Always comment on particular category blogs , if you approach for your own blog or your company blog's services , try to comment in descent way with proper knowledge and read of that blog , you can stuff your targeted keywords in that comment for promote your website .
Dear, we know that Blog Comments are very helpful for getting quality backlinks and relevant visitors traffic...I also agree with that point...
Blog commenting is great but good pr blogs dont accepts comments very easily, is there anyone who can pass the list of site with good pr where i can post comments and get approved quickly.
Try to read the post and get along with it and if you are unable to get with it and there are no irrelevant comments apporved on it, then i would suggest you to leace that page and carry on with other.
Always do blog commenting on your niche , and try to comment on relevant topic , so it may be useful and give you backlink