I learned a lot on the next picture, about color. I was reading Marta Dalhig's tutorial on noses, so I drew pretty much the same picture.
I learned about contrasts, dark grey looks white next to dark colors. It sounds obvious, but now it clicked. It looks so nice making subtle contrasts.
Also on how to pick colors, instead of mixing them on the document, like I see a lot of people do, I up the amount of... Red or something in the Color picker. I'm just used to Flash so this works for me.
40 minute drawing
I realized I needed to study eyes and noses more. But lips especially, but my hand started to cramp up, so I'll do that tomorrow.