5. Reduce the contrast of values as objects recede. This is related to Details in Front, Lost Edges in Back, especially since one way to highlight detail is to have your lightest and darkest values next to each other. The farther back in the picture plane something is, the less contrast there should be.
Here’s a great example from someone I wish did workshops, Mark Haworth (“Fredericksburg Autumn”, http://www.markhaworth.com):
You can see that every tree, every building, are reduced in value contrast as they recede.
This effect is especially apparent in foggy or misty scenes, like this one from Skip Whitcomb (“Yellowstone Fog”, http://www.skipwhitcomb.com).
See how the pines trees get lighter and lighter in value the farther away they are?
To be continued.....