Post interesting content. Get it in front of people who are apt to share links to things they like.

HN's patio11 has a lot of posts about his content creation strategy that you can pretty much directly rip off and they'll be useful: http://www.kalzumeus.com/greatest-hits/ (scroll down to "SEO", though really all of those posts are pretty good)

Think about what your potential customers will be searching for when they are trying to address the need that your product fulfills. Then, provide real value to your potential customers on your website in the form of articles and other helpful advice. It sounds too simple, but most of the "seo tactics" that so called seo experts talk about just don't work in the long-term. They are just an attempt to game the system.

I am wondering what your actual goal is. I am wondering if explaining that would get more replies. I would love to hear more on the topic. I am trying to figure out how to get more traffic to my sites. I assume that is the same thing but maybe there are a variety of tactics beyond "SEO"?