Organic traffic or free traffic is very simple to explain, but a bit harder to implement. Organic traffic comes from the search engines, other sites that link back to your site and from direct access via other online and offline methods. While organic traffic is usually thought of as search engine traffic, as you can see, it can come from other sources as well.
In the interest of simplicity, this post will center around how to get a steady flow of visitors from the search engines. There is tons of material out there about how to get the search engines to recognize and love your site. However, while there's plenty of opinions, what I've found to work for me consistently is onpage SEO.