Color Outside the Lines Sometimes. In some circumstances, like this one, you can color outside the lines because you'll cut the piece out afterwards. This allows you to use large consistent strokes, as you can see in the red kidney above and on the right. This is an especially helpful tip for younger students who are coloring the organs in this My Body project. (Just be sure not to use this tactic on the upper half of the heart in the My Body book because we won't trim around all those veins and arteries.)
Then you can also create a texture effect. Just cover the drawing with a light stroke first then follow with rough, think strokes to serve as details . texture. This can also be applied when you're using colored pencils. And you can also create a light, smooth look with crayons. Just color your drawing with very rough and thick strokes (this might make the drawing look messy at first) then rub off the excess color with cotton or scratch paper.