To keep people interested in a blog it's best if there is a new post every day. That's one of the reasons I blog here when I see a few days have gone by without fresh material.
A blog also should be plugged on Twitter and Facebook--so if you have your own blog be sure you let people know what you've blogged about each day. (Of course if you are on any other social sites, go ahead and promote your blog there too. Or use Ping.fm and your post will go wherever you're signed up.
When you blog always check to see if anyone has left a comment. You might want to acknowledge with another comment. If you've been asked to post on someone else's blog, be sure to thank them through the comment and check to see if anyone else comments.
When visiting anyone's blog, leave a comment. Sign up as a follower on other people's blogs. I'd love to have you sign up as a follower of mine: http://marilynmeredith.blogspot. com
Blogging is another way of gaining name recognition. As an author that what you want--name recognition.
When responding to a blog, make a comment rather than a short blog unless you have quite a lot to say on the subject.
Anyway, that's my advice and tips for the day.