As discussed, participate in forums, do article, PR which can help a lot. Even social bookmarking can drive traffic. Write blogs and give valuable comments to the site you visit.
links to a site are very important, if not the most important way to get a website on the top of all the search engines. without effective link stategy, you really can't get your site up on the first page of the search engines.
Content plays an effective role for your visibility anywhere. You can adopt any link building strategy but keep in mind the quality and uniqueness of your content, choose right title, keywords and place them accordingly.