An essential tool, I use the Prismacolor Col-erase Non-photo Blue Pencil daily to lay in the basic shapes and capture the posture, proportions, and angles in most of my drawings. I then go over these lines with graphite and sometimes watercolor. Even though the pencil is erasable, I generally do not erase the lines. This pencil is so light and non distracting that it almost seems to magically disappear when you cover it with graphite. You could just draw lightly with graphite pencil for your starter lines but these lines end up showing much more than the non-photo blue guidelines.