A while back I posted the finished Dragon Turtle I created for a D&D Homebrew group on Tumblr. After sorting though piles of sketches around my desk, I collected some of the preliminary sketches for the turtle design.
Most of the time I sketch with a colored pencil, usually red or blue sometimes orange. Then I smudge the entire drawing with some cloth, softening the underdrawing. And because my sleeve would do the same. I'll render the drawing with a variety of pencils and easers switching between the two till the drawings done.