I'm sorry you quit there. Those guys were pretty good. Very inspiring too!
To be a good artist, you gotta observe everything you see and how its shape changes the color. That's how I learned my metal shading.
Their way of drawing is a lot more efficient too, since if you draw the base color as a huge block, there wouldn't be an outline to interfere....just like with heads!
pen and paper experience is pretty important to electronic. Since PS work usually revolves around technique and the understanding of how the functions work, while with paper, you don't have to worry about what you are doing, just what you see and how that translates onto paper.
Like one less step you have to go through.
Trees can be deceptively difficult