Step1
Step one: compass-drawn 3/4 circle, opening downward.
Using the compass, draw a circle on your drawing paper. Don't complete the arc, leave about a quarter of it open at the bottom. Do it in a size that will leave some space on all sides on the paper, more space at the bottom. Don't ink this till it's finished. Or you can draw a freehand arc if you're good at drawing circles, it doesn't need to be precise. I'm using charcoal so you can see my sample skull easily in the scan. Draw lightly if you want to ink it.
I drew this sample with the compass before going over it with charcoal, if you're wondering.
Step2
Step two: eyeholes, nose holes and sides of upper jaw and teeth.
Draw two short lines straight down from the opening. Draw in the eye holes placed the way I have -- not right up toward the top, but around where the middle of the head would be. Those two lines are going to be the sides of the top jaw and the teeth.
Draw two teardrop shapes to outline the nasal opening. Place them under the eye holes and between them. Don't make the nasal opening too large.
Step3
Step three: Eyeholes and nasal opening filled in, teeth drawn.
Black in the eye holes and nose holes. If you want, you can draw or paint glowing red eyes in them, but be sure to leave plenty of space around them if you do. Black in the nose holes and connect them with short curved lines at the top, so that it's one vaguely triangular hole with a ridge up the middle.
Draw the teeth. Put one slightly curved line halfway down the short lines, another at the bottom, and another at the middle. Cross it with vertical lines to define separate teeth.
Step4
Finished skull and crossbones!
Finish by drawing the jawline. This is an irregular shaped line, but easier to figure out once you have the teeth in.
For some piratical fun, add crossed bones under the skull. You can fill in the background black for a pirate flag, or pencil this, cut it out and paste it on black paper. Or transfer it to black paper and paint in the white parts with poster paint.
Be sure to draw the top crossed bone first. Make irregular bumps at the end, if you're not sure how it looks, look at a chicken leg bone. A little curving line helps define the joint ends of the bone as three dimensional.
Spray with Krylon matte fixative if you used charcoal, Conte crayon or black pastel stick. If you draw this in pencil, now is the time to ink your drawing with black marker or brush pen.
Skulls are cool for t-shirt designs too. You can draw this design in white chalk on a black t-shirt, then fill it in with white fabric paint or fabric crayon. Do it in black on white first, so that you know where the lines are and paint between them, or draw the lines with black fabric paint and then fill in between them with white.
To learn a more realistic style of drawing skulls, look at anatomy books and sites. Copy technical drawings of real skulls, or sketch from a plastic skull with pencil until you have all the details and shading. This skull is intended as a simple iconic cartoon anyone can draw.
There are as many uses for this design as there are goths, Halloween fanciers or bikers. Have fun and use it wherever you want!