Make sure you have a focal point for your photograph. This should be the first thing that the viewer's eye is drawn to. Whether it's a flower, a person, or a bird, every shot you take should have a specific focal point. Don't only think about what the focal point is, but figure out the best spot for it in the shot.
http://adorama.com In this episode of Exploring Photography with Mark Wallace, Mark introduces the basics of proper exposure with the exposure triangle.