Galen Rowell spoke of the importance of using edges in photography. In an attempt to improve my own photography, I will often look for edges that I can incorporate into my compositions.
In this photograph there are many edges that came into play. This image includes the edge of morning light - Dawn, foreground and mid-ground edges of the rolling hills, and the edge of the fog. Also, In this image, the colorful light is created by another edge- the front edge of an approaching storm.