I've determined over the years that there are three types of GOOD artwork:
1. The kind that people love to look at (but not buy)
2. The kind that people love and will buy (once)
3. The kind that people will buy and fill their homes with.
The first kind is the bane of any artist's existence. People love your work, ooh and aah over it at shows, tell you how amazing it is but you don't have get any sales. It's hard to understand why people would love to look at a work but not buy it, but it is a very real fact that we have to accept.
I once saw a painting of a farm tractor that was exquisitely done. I thought it was an amazing painting and the artist did a remarkable job. However, I didn't buy it (price not withstanding) because I have no interest in putting farm tractors on my walls. Jack White says that people must emotionally connect to a painting before they purchase it. He's right.
The second kind of artwork is certainly better than the first but it brings in no repeat customers. These paintings may depict subjects like Fenway Park or Saratoga--places that evoke warm memories for the viewer. However, the vast majority of buyers will be satisfied with one depiction of their favorite subject. One and done. Specialized subjects like equine, sports, or mechanical renderings may very well fall into this category. It takes a lot of effort to get one customer, so repeat business should be the goal of any artist.
The third kind of good artwork is obviously something we all strive for. As artists we hope to attract buyers who purchase several of our paintings and and are delighted to display them in several rooms of their home. This happens when you have a subject matter that resonates with the buyer, have a distinct enough style that they are attracted to and enough variety in your offerings that the collector can achieve some variety on their walls.