First you have to become familiar with modern art movements most important. The highlights are Art Deco Art, Impressionism, Fauvism, Expressionism, Art Deco, Art Nouveau, Cubism, Surrealism, Pop Art and Op-Art. Understanding these movements will help you decide what you're looking for and which lead to the artwork for purchase. A simple Internet search will give you a wealth of information for each of the movements and examples of photos.
The second step is to identify movements that you like. Every movement has its famous modern art and artists of the brand. For example, some of the biggest names and their movements are Dali's surrealism, fauvism including Matisse, Picasso Art Nouveau and Impressionism of Monet have. Knowing that interest art movement that will help you limit your choice to buy art.
If you are looking for art that will have a return on investment possible to follow a well-known modern artist. Many of these artists have pieces that will go on sale at auction. An Internet search will give you a good basis for the amount of the works of your favorite artists are in their favor.
If you're on a limited budget in the best of your original purchase modern paintings by talented artists. The selection is readily available and that price difference is huge. A good source of original modern art contempogallery.com.
In conclusion, do your homework. A little field work now will pay off big in the future. When it comes to research your potential artists, the internet is your friend. Knowing what you like and know your artists.