From my recent blog post on http://petermahoney.net:

Here’s a top tip. Once a week, read a really popular blog about your industry. Take 10 minutes to write your own thoughts on the subject, and post that to your blog. Then comment on the industry blog saying, “Hey, I’ve been thinking about this a lot too, and here’s my recent blog post that might help enlighten things.” Boom. Your traffic goes up, and you have original content linked to on a popular site—it doesn’t matter that you did it yourself.