The tutorials are indeed very useful. By the way, sir, what kind of program do you use to sketch? I find it very hard to sketch something everytime. Most of the time, I simply move my mouse to colour then use eraser to erase until a border of the item that I want appears. But, it indeed consumes a lot of time.
EDIT: And.. um.. what do you apply to make the sketch looks so real? I was following the tutorial on making the crystal and suddenly the crystal you drew seems so real on the next step.
EDIT: I have spent hours just for sketching and shading that crystal >< and yet I can't get it right! Arghh... why is it so hard?