Six ways to create the illusion of space
Linear perspective
By using either one point perspective, two Perspective, or three point perspective (Birdseye view and worm's eye view) an artist can create the illusion of space. When your perspective is a drawing method that uses lines to draw objects in space
Placement
Generally, objects that are positioned lower on the picture will appear closer than objects that are positioned higher on the picture plane.
Detail
Objects that are closer appear more detailed than objects further away
Color and a value
Objects that are closer to a viewer appear darker in value and warmer in color. Objects that are further away appear lighter in value and cooler in color.
Size or scale
Objects that are closer to a viewer appear larger than objects that are further off in the distance. Scale reference to the size of an object ( a whole) in relationship to another object (another whole).
Overlapping
When one object covers part of the second object, the first seems to be closer to the viewer.