framing
The world is full of objects which make perfect natural frames, such as trees, archways and holes. By placing these around the edge of the composition you help to isolate the main subject from the outside world. The result is a more focused image which draws your eye naturally to the main point of interest.
Whether it be a very literal frame (that went through a popular “prop” phase), environmental, or structural framing, framing with light or lack of light, they all work well to bring the viewer's eye to your subject. Framing is actually defined by wikipedia as 'a technique used to bring focus to a subject'.