When you comment on someones post you want to tell them why you’re commenting. You also want to know what you’re talking about and sound like you have some sense. Then you need to ask questions about how they do things on their blogs, and if you know advice you could give them then you should help them out and give that advice. Lastly, you should always leave your web address so that they can visit your blog and see like what you blog about and comment on yours if they want to.