I use WordPress for my websites. WordPress is known as a blogging tool but really it is very flexible and can be used for all types of websites, including e-commerce.
There are amazing plugins that you simply download and activate within WordPress. If you use the search based keywords tool from Google, you can come up with a list of excellent keywords to put into these search plugins. In addition, there is a Google XML site map plugin. The point is that whenever you add new content, your site is automatically remapped and Google is notified.
Using the various PING plugins is useful too.
Finally, I would recommend this for thorough training in how to build traffic:
http://bit.ly/4JDBDD.