During my tenure I have dealt with everything from a hobbyist artist to a professional with 30 years of experience under their belt. All these artists allowed me to learn from them and pick up bits and pieces of what it takes to make it in art. Also, they helped me define my own success in this field.
Since art is not something people necessarily need (like a toothpaste or food), it is difficult to sell. Art is a discretionary purchase that many people are not accustomed to. Especially here in Midwest, it is viewed as frivolous and there isn't much culture of art consumption. Therefore we are really catering to a very small percent of population, the sophisticated crowd. These people are difficult to reach. Even if you can paint a Mona Lisa per day, if you don't have access to a buyer it won't matter how good is your art.
Instead of catering only to those rich folks who don't ask how much is something they truly like, most artists produce art that is accessible and in low price ranges. Many nice pieces of art are available for less than $100 in today's economy. The people who buy inexpensive art are very price sensitive, and they show difference in purchasing behavior for as little as five dollars. For this group, which is the greater majority, the trick is to price art to the market. This is the main point where artists fail. Most artists tend to overprice their work and therefore don't sell anything.
If you receive consistent compliments about your art, organize art openings and shows, if your art is made well, there should be no reason that you can't sell it. The major reason we don't is because it is too expensive to the people who have all kinds of bills and worries.
There is something very valuable I have learned from art veterans. They have made tons and tons of art that nobody wanted to buy. As time went along, those veterans have specialized to make a line of artwork that is proven to sell at a given low price point. This lower priced line artists call their "bread and butter". Anything that you can sell a lot of is beneficial. The other group of items is upscale, expensive kind and artists don't sell a lot of these more expensive items but occasionally they do. The good combination of products seems to be the most successful.
The best advice I would give to any artist starting out is to 1. make a lot of art because not all art will sell, 2. learn what is their artistic niche and 3. price reasonably. The most common mistake is pricing your art as much as you see in some established art gallery. Those art galleries have access to buyers that you don't. Artists who enter the gallery system receive a glorified status, and their art may not be any better than yours.
If I look over my portfolio, almost every painting had a buyer at some point but many buyers have passed them because of the price. And that is OK. We don't have to make our art affordable to everybody. There are pieces that I am emotionally attached to, and to me they are worth more. Every artist knows when a piece turns out exceptionally well, and those pieces will be your premium product.
I hope this helps a bit, and don't hesitate to ask questions (if you have any). Good night!