You didn't mention about blog writing.

By adding a blog to your website, you will not only help keep your business and website higher in the search engine rankings, but may also attract new clients who would have otherwise overlooked your business. Although providing regularly updated, well-written and informative blog posts can be demanding, the subsequent increase in site traffic could translate to higher sales and profit.

Also the visitors who like your blog post could submit it to social bookmarking sites such as Digg, StumbleUpon, Delicious and so on in order to share it with other people, which could lead to a traffic boost to your blog.

Good Luck.