For part one, please see Using SEO to get Your Selling Blog Noticed.
For part two, please see SEO and Links .
Did you know that there's a connection between leaving blog comments and SEO link building? Indeedy there is! Usually if yours is one of the first few comments, you’re more likely to get noticed simply because people often don’t have time to read through all of the comments. Commenting just to comment – like those silly “First” comments you see on various sites – doesn’t help. In fact, it will get people annoyed at you! But even if you're not one of the first few people to comment, you're at least getting your link out there, which is certainly a good thing, as I've mentioned in my previous posts about Blogging and SEO.
Additionally, if you leave your blog url in your comment, that’s oftentimes seen as the dreaded spam. Remember, when you comment, there’s a place to put your url, so if people want to find you, they can. The exception to the no spamming your url in the comments section is if you’ve actually written a blog post about the topic at hand. Rather than writing a whole blog post in the comments section, sharing your link to your particular blog post – as opposed to your general blog – isn’t seen as spam. But only do this when it’s germane to the particular topic you’re commenting on.
Also, when making comments, make sure you’re respectful to the blogger and his/her readers. You are, after all, in a person’s online “house,” and they’re allowing you in. Be courteous.
As to reading the comments people have left on your blog, be courteous right back! If any of the people who have commented on your blog ask a question, by all means, answer it! Blogging is kind of like a dialog with people around the country and the world. It’s a great way of meeting people and getting to know them. Treating those who visit your blog with respect will go a long way, and they’ll more likely want to return to read what you have to say.