In Terry's art history class on the history of illustration there was a slide containing Pyle's precepts for good picture making. I thought these were great reminders, so I made a little gift for you all!
Below are a desktop wallpaper and 8.5"x11" printable version of those precepts, based on the original poster. It's been very helpful to me to have these in front of my face when working!
Enjoy, and happy picture making!