Thanks a lot! I'm studying here http://artac.org/
You're right about the digital paintings! I've been trying to put digital painting on the back burner: I want to get better at oil painting first and only do more digital once my foundations are more solid, which is gonna take a while.. It's more of a guilty pleasure (I'm considering switching to painter and learning to use that).
I've noticed that improvements in oil painting convert exponentially into improvements in digital painting.
Since I'm not very happy with my handling of color, here's a color chart, with varying hue-value-chroma in the shade of yellow ochre, to show how I spent my morning, going to do these again in the next days. Sorry for the crappy cell phone photo..doesn't really show the color differences but maybe someone can get an idea for a study practice...