Perspective is the technique that artists use to project the illusion of three-dimensional space onto a two-dimensional surface.
Perspective helps to create a sense of depth–a sense of receding space.
Artists achieve perspective in several different ways:
by making objects in the foreground larger than those in the background
by making objects at the bottom of the composition larger than those at the top
by using lighter colors and fuzzier edges to suggest the distant objects and space
by using mathematical or linear perspective, where the recession is directed towards a vanishing point.