Google for a picture of him.Print it out in 8 x 10 on anything. Using a very fine tipped marker, use your ruler and graph out the printed copy in 1" increments. (Draw the lines). Now on your art paper using a soft pencil, draw the same graph lines very lightly. Fill in each box with only the image that is there on your picture graph,embellishing or making it simpler if you want. A lot of caricature artists and painters use this method. Have Fun.