composition and aesthetics

This is a pretty good link:

http://findarticles.com/p/articles/mi_m1306/is_8_69/ai_106559912 

In this article, the author gives a basic overview of composition and the idea involving centering photo's. He discusses the fact that the eye is naturally drawn to the top, and some argue the top left. He also gives practical tips for the photographer, such as avoiding vertically symmetrical compositions, or "breaking the symmetry" when placing the main object in the center (adding another element to the right or left of the photo). 

I did not find a ton on aesthetics, and although I never ever use this source, I finally reverted to reading the definition from Wikipedia. Even that was vague, but from what I could gather aesthetics has to do with the "reflection" of art - that is, the ideas and meaning behind the art, the reaction the viewer has toward the art, and the effect it has on people.