Watch the video and look specifically at the Paintings Paul Cezanne did of the skulls
Look at your skull you are drawing some questions to ask:
Where does the light hit the brightest?
Where is the most shadow?
Now look at the shape find the contour line of the skull
1. Begin Drawing using the contour line method.
2. Add detail
3. Start creating the form of the skull using the different values of gray from white to the darkest areas of the skull.