Want to learn more about composition? Ok, then here is a PDF "Artistic Composition for Computer Graphics" where Bruce Gooch and Mario Costa Sousa explain some of the rules of composition. For example:

Artists have their own heuristics for choosing a viewing direction that are reasonably consistent with the psychology results: pick an off-axis view from a natural eye height. Direct 45 degree angles are avoided. Another rule is to have the projections of front/side/top of the object to have relative areas of 4/2/1 on the canvas (often expressed as 55%/30%/15%). The front and side dimensions can be exchanged depending on the object.

This document is full of concise explanations of such rules. You may learn a few (if not many) things about composition.