As a general rule, if a photographer is shooting from a public space, such as a street or a park, he or she will usually have the right to do so without the consent of the subjects. Generally speaking, if you can see it from a public space, you can take a picture of it. Street photography is a perfect example.
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).