Very cool man! I don't think I can give you any real critique since personally I think you're miles ahead of me in terms of skill, but as a total beginner to digital painting, this video's a great help! I've got a better idea of how I should work with coloring using a tablet now.
How long did it take you to color that?
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Hey man, it's pretty cool that you did a video and showed how you work. I hate to sound like I troll but I believe there are alot of things you should be doing before running ahead and detailing. The main thing I noticed was that you aren't blocking in any lighting on a larger scale. Try to think of the face as a much more simple form and work out where the shadows would fall from the cheeks, eyebrows, nose, etc., etc.
I'd also suggest avoiding the use of black when doing your shadows unless the picture is in a greyscale. Try a less saturated complimentary color.
Prom has a great essay-esque thing that touches on this that he just updated last week (holy shit I just found this out myself, time to re-read).
All the cool kids ignore my ketchook.