I start out trying to identify the particular shading of the pine branch, and this particular picture I am using two different lightness/darkness to identify shape and shadow. The darker one I can see the definition of the sprouts, and on the lighter version I can better see the pine needle definition. You can click on the pictures to see a large version of the photo.
Apparently some women (young latina gang-bangers) use Sharpies to draw on their eyebrows...this I saw on the George Lopez show. I don't use my Sharpies for that. Using a fine sharpie I outline the pine sprouts shapes and shading on one drawing and the pine needles on the other drawing.