Start with an average sized, pear shaped pumpkin with thick skin. You need a pumpkin with thick skin because you will be carving away some of the pumpkin's surface. We are carving our pumpkin upside down to match the shape of a skull.
Hold the pumpkin upside-down. Decide where the eyes, nose and mouth will be located. Use a dry-erase marker to outline the two eye sockets, an opening for the nose cavity and a straight line with two crescent shapes on both ends for the mouth. If needed, print a picture of a skull as a reference when drawing the facial features.
Cut the outlines using a carving tool or knife. These holes will serve as reference points when shaping the contours of the skull. For the mouth, just cut a straight line; the teeth will be carved after the skull is shaved and formed.