The basic start of drawing a Zombie is that you can draw an oval shape for the head and build on the initial sketch that way which is usually the easiest way to draw. I use either mechanical pencils to draw or popper pencils or sometimes a 2B or HB pencil to do the pencil drawing. The drawing is built up by sketching roughly at first to build up the face and then when you are happy you can start to add shading and other details.
The inking is done with a black gel ink pen or a berol fine liner ink pen with minimal cross hatching to simulate shadows under the eyes.
I used Crayola Twistable pencils to color the head of this rotten Zombie drawing.