Six months ago I decided I was going to re-color all 75 pages of The Hall Monitor, which I had 'completed' back in 2008. My first step was to try to actually learn how to color! I hit the books and here are my first attempts.
I read that a good way to make colors work together is to give them a common base. I started each study with a light blue and laid new colors over top with a low opacity brush in Photoshop. The result were greens that had blue in them, reds that had blue in them, yellows that have blue in them, etc, etc.