Social content: make sure that you have something “social” on your site, whether it’s a blog, forum or even your very own social networking. The easiest and best of these is a blog in my opinion.

Update often: always provide fresh content. Update the social aspect of your site often. This will really help you with ranking.

Share and share alike: make sure that your content is easy to share. If you don’t have sharing widgets on your site (Upload to Facebook, Tweet This!, etc.) then get your designer to add it to the site asap. Most blogging software comes with this all ready to go.