I thought I would share a couple of mental exercises that I developed to help myself "see" better for my photography -
I wrote them in a blog post -
http://kellenheller.blogspot.com/2005/11/improve-your-photography-without-using.html (not selling anything!!)
Doing both of these exercises over time has helped me a great deal, both with composition, subjects, visualization, and lighting. Let me know what you think.