Learn about the art first. Know which forms of arts are more popular than others and also what people like about art. Putting an exhibition of your art collection at a right time can also help you earn a handsome amount. Understanding the market segmentation is also essential for commercial success of the art collection. For example, someone who genuinely loves art can buy any piece of art no matter what the price is, if it is really a good piece.
If you are planning to buy art work only for reselling purpose, try to arrange more than one artist as your direct purchasing source. You can buy their work on a regular basis and resell it in the market. You can also help them organize exhibition of their work and then take out a certain percentage.
You should also attend art exhibitions regularly. This will help you understand the art better, connect you with right people and also have an understanding what type of art people like. This will help you completely immerse into the art market, and you might be able to achieve commercial success in a short period of time.
Search for the places where you can buy quality art work. This can be online art work display centers, websites or shops. Sometimes artists have their own shops and exhibition centers where people can buy their work directly. By searching the market you can find places where you can negotiate on the price and you can earn good money by reselling them.
Think how much money you can invest for the purpose. Be assured that this investment is not rewarding immediately. So you should be patient. It takes time to resell your art work, but whenever you do you can surely earn some healthy amount on them.