Facial proportions can vary according to ethnic background and gender. Traditionally men have more angular faces and more pronounced brow just above the eyebrow line. Examine the images shown to see how the eyes fall in the middle of the entire skull, between the tip of the head and chin. In-between the eyes is a space equal to the width of one of the eyes. Halfway between the eyes and the tip of the chin is the line where the mouth opening will fall. Although the model on the left is a young adult female, the proportions are the same as an adult. Her features are merely softer and less angular than seen in an older mature looking individual.
Remember these are merely guidelines and will need to be adjusted to fit the subject that you are depicting. Below is that of a middle-aged male’s profile. When you are drawing a subject keep in mind where your light source is coming from, the same rules apply to drawing a human being as to drawing anything else. The trick is to be objective and to draw what you see and not what you think you know. Look at the subject carefully and try to look at the person you are drawing more than the paper you are drawing on. Always work from life whenever possible, if you can not find a model or do not feel comfortable doing so as of yet, just use a mirror and do a self-portrait.