I only had two classes to work on this. First, we had to upscale a smaller version of this image to the original size by figuring out the measurements. Then we had to make a grid and apply our measurements to make our grid accurate to the smaller image. Using the new grid, we eyeballed patterns and lines and all that FUN stuff. Then using a light table, we had to recreate the missing portion by sight alone and with zero line strokes. I had problems with his eye. :/

Drawn on a solid graphite number two pencil