Generally speaking, paintings with light colors sell more quickly than paintings with dark colors. Subjects that sell well are: Madonna and Child, Landscapes, Flower paintings, Still Lifes (free of morbid props i.e., dead birds, etc.), Nudes, Marine pictures, Abstracts and Surrealism. Subject matter is important. It has been said that paintings with cows and hens in them collect dust while the same paintings with bulls and roosters sell.