Adding depth to a composition adds interest for the viewer. Depending upon your subject and goal, you can create depth in a composition by placing the subject of the scene in the center and adding foreground elements around the sides. You can also employ natural and man-made frames such as trees, arches, windows, and doors.
To apply this rule, frame the main subject in the background with supporting foreground elements around the sides.
Zoom in and out to optimize the balance between your foreground and background elements.