I was trying to get different shades by using varying pressure with my pencil, but alas, I still need to work on that. I've always had a huge problem with using too much pressure, due to the way I have always held my pencil when I was a kid, and the fact that I'm a lefty causes me to drag the side of my hand across the picture. It's hard to mentally stop doing that after doing it for 20 some years.