In bad photography, often half of a body will make it into the photo. A good photograph focuses on at least one subject, makes that subject clear in the photo, and composes the entire image in a way that is visual appealing (usually relying on the rule of thirds.)
What Sells Best On Shutterstock?
Some types of photos that sell best are Portrait Photography, Food Photography, Landscapes (usually with people) and fine art photography (artsy).