Short answer: No one can help you without knowing more about your website.

Long answer: There are two sides of your e-commerce business and either or both could need improvement. You have visitor acquisition (getting people to your site) and conversion (turning those visitors into customers). I'll touch on each just a little.

Visitor Acquisition: How many visitors do you have to your website? Where are they coming from? You want qualified traffic... meaning the people visiting are actively looking to actually buy some art. You can buy 100,000 clicks on Fiverr but it won't convert. You can find targeted qualified traffic on paid search engines like Google or Bing, on Facebook and other social channels, and through organic search engine optimization. Once you've got a good stream of traffic to your site then you can look at converting them into customers...

Customer Conversion: The average e-commerce conversion rate across all verticals is around 2%, but it's much lower for luxury goods, high priced items, electronics or any other products that typically require more thought that goes into the purchase. What's your e-commerce conversion rate? (if you don't have e-commerce tracking setup in Google Analytics you can just take your # of sales / number of unique visitors over a period of time).

There are a lot of factors that affect conversion. Is your site trustworthy? Is it secure? Are your products featured well, so visitors can get a really good idea of what they are purchasing? What is your return policy? How much is shipping? When will customers receive their items?

There are lots of reasons why your site might not be converting, but without seeing it I can't make specific recommendations. If you are getting lots of visitors (thousands per month) and making no sales, you need to focus on improving your website to increase your conversion rate (also known as Conversion Rate Optimization or CRO). If you don't have much traffic at all, like just a few hundred per month, then you need to focus on getting more qualified traffic either through social media, PR, organic search engine optimization or though paid ads.