Hey,
Hopefully I'm not posting too much, but I wanted to put up the following images just in case they help someone.
After I watched the "Draw a Tree" segment of How to Draw Everything, I drew the first tree, then thought so little of the inked version that I decided I hadn't really been paying attention. (I thought so little of it that I drew another version of the tree on back, that's the tone that's bleeding through).
The next tree I drew, I'd paid attention to the lesson better, but still didn't like the way things came out, so I ended up watching the lesson a third time, and thinking some more, and then did the third tree.
Perfect? No, but the point that I wanted to make is that the first tree you draw isn't the last tree. And that it might be worth while to go back and watch videos, if you think you've missed something. 
