when I was studying photography we went through a list of nearly 50 image elements and the basic were the first 6: shape, tone, color, order, texture and volume. Of course these are all technical and do not address the more subjective aspects of what makes a good photograph.

I was listening to a Brooks Jensen podcast (#354) in which he goes through the characteristics of what he considers a bad photograph, on his list are: pretentious, arrogance, shallowness, boring. Something to think about.