There are a number of good books that help you think about composition. One that I think is worth reading is "Learning to see creatively" by Bryan Peterson (http://www.amazon.com/gp/product/081...s&n=283155
Composition is a huge field, and there are at least as many ways of seeing as there are people who can see. Developing your own aesthetic sense is the most critical paart of becoming a photographer. Technical issues will arise, and you will have to overcome them as they impede your ability to effectuate the image you see in your mind's eye. But the really hard part, to my way of thinking, is to visualize the shot that you want to have in the first place.