I have traced much of my painting frustrations lately to a particular suspect: color. I believe I do not naturally have a good sense of color and that it needs to be cultivated. So recently I took a Color Intensive at the Cambridge Center. The instructor was no color genius: I asked many of what I thought were basic questions for which he seemed to lack answers, but he directed exercises with the color wheel that I did learn a lot from. It turns out my color wheel education was severely limited- it is in fact a very useful tool and yes there is a science behind a good palette (even though some artists understand and apply this naturally). Also I have a new rule that I will never use simple bottled brown, grey or black again. Harmony is created by relating the colors on the palette together and subtle harmonious color goes a long way toward improving the painting. Brown grey and black are much more interested when created from complimentary colors.
I have also started using a new online tool which allows you to create and save color pallets online. It is called Colourlovers, and while most people use it for graphic design or just for fun, I was able to successfully apply a saved palette to a newly started painting today. When I strayed away from the palette, I quickly noticed the disaster it was creating and cleaned it back up.