Composition is where lines, tone or color are put on a piece of paper, canvas or photograph.
Putting something in the center is strong, calm, solid, still, stable or boring depending on how this placement works with your subject. The rule of thirds in photography breaks up the space so it is easier to think about the options we have with composition. The composition should match or enhance the subject. If it does that, it works. If a composition causes the eye to travel off the picture plane or land on the most uninteresting part of the picture, for example a random area of blotchy highlight that has nothing to do with the subject – it does not work. The eye goes to the most interesting part of a photograph. That is the result of composition. Learn to use composition to emphasize and strengthen a picture. Make the viewer see what is important, beautiful and significant. Use composition as a tool to make pictures stronger.
“It’s not what a movie is about, it’s how it is about it.” -Roger Ebert
This is also true of pictures.