Recently, I stumbled onto the on-line showcase, Xanadu Gallery, based in Scottsdale, Arizona. Though I don't know anything about them in terms of their on-line sales, I was interested in three aspects of their website.
First, their blog has lots of information about marketing art, aimed at individual artists. Topics discussed include defining your success as an artist, the importance of productivity, and difficulties in finding local representation.
As well, their website features video downloads on helpful topics like shipping your work, creating a powerful portfolio, and making the most of your website. Thirdly, podcasts are available on topics like the benefits of blogging for artists and how to write a slammin' blog post.
Studies have shown that "successful" artists often spend half their working hours, or more, on business-related tasks. The information on this site may help you to optimize that effort. Consider subscribing to updates.