But how do you define composition?

Pattern

As there are patterns to be seen everywhere, this is a good subject in art.  You can achieve stunning images by focusing on these patterns.  Highlighting broken patterns is also good.

Symmetry

Symmetry could go both ways.  It could be good if you have a symmetrical view with an amazing point of interest and great composition.  The key here is the point of interest.  If you have a weak point of interest, or none at all, your photo could be boring.  It is advisable to capture both situations to judge which one is better.

Texture

You can make your art come to life by adding texture.  Texture can be achieved through strategic positioning of lighting.  This way, the two dimensional piece could have a three dimensional effect.

Depth of Field

Depending on your depth of field, you can either separate your subject from the surroundings, or you can integrate your subject with the foreground and background.  For the former, you can use a shallow depth of field, while the latter requires a larger depth of field.  Depth of field, hence, will largely affect the composition of your art.

Lines

Lines can be used to lead the viewer to look at crucial elements in a picture and establish the feeling depicted in the image.  Before capturing a scene, you should first be aware if there are any horizontal, vertical or converging lines covered in the shot.  If there is, you should utilize it.