There are many subtle variations in human faces, but you can generally organize position, shape and proportion of major facial features in a basic line drawing. The best place to start with a drawing of a face is with a straight on view. The face has an oval shape that has it’s longest dimension from chin to forehead (or hair line). In that dimension it is approximately equally spaced from the hair line to eyebrows, then from eyebrows to the bottom of the nose, and finally from the bottom of the nose to the chin. In an approximate drawing of an oval shaped face each of those three segments could be set at 1 inch and the long length of the oval will then be 3 inches.
Then, at it’s widest point on the horizontal–from ear to ear across the eyes–the distance will be about 2 1/8 inches. Remember the eyes on this scale will be placed about 1/4 inch below below the eyebrows. The eyes will be about equally spaced on each side of the center vertical line, at a distance apart of about 7/8 inches. This will allow the two eyes and the point just under the nostrils of the nose to form an equilateral triangle. The line of the mouth will then be centered about 3/8 inch below the nose nostrils.
Most artists who are interested in drawing human faces or portraits will not make exact measurements of the type shown above, but will at least note approximate placement of the major facial features. For a direct on view of the oval shaped face, I think it’s useful even though many variations will exist. If the mouth, nose, eyes, eyebrows and ears are distorted even slightly relative to one another, the appearance of a face familiar to you can be rather distorted. It is still true that there are differences between the facial features of different humans such as larger ears, wider or distorted noses, bushy and offset eyebrows, distorted chins, and so forth. Some have wider or oval distorted heads, high foreheads, sunken cheeks or high cheekbones that may not even be noticeable in most others. Many of these differences are especially interesting as they will be emphasized in caricatures or as the basis of a political cartoon if you happen to be important enough to be a target of political cartoonists.
In drawing a face once you have its general dimensions in mind, it’s best to sketch lightly and start with the eyes. Then also sketch in the approximate position of the nose, mouth and eyebrows. This approach should leave you with the potential for a good likeness. This allows you to establish the position of the forehead and the chin and then the shorter horizontal dimension of the oval axis of the face and placement of the ears. The face is then framed, and you can draw in hair, neck and shoulders. But while you may have proportions generally correct and some details added the sketch may not yet look like someone. This should improve as you add detail and properly work out shadowing and special details of the face you are drawing.
Extracting a likeness in a pencil drawing of a face is not always easy even when you have the positioning, shapes and proportion of major features has been well-accomplished. Try different faces from photos, newspapers and magazines. Just keep drawing. Some attempts will yield great likenesses. Some will not–until you finally see a small, but perhaps unique distinction in the face and correct the drawing.
Drawings of faces that are not viewed directly will include side views (right or left) and views that are only slightly off to one side or the other. These views can be further modified by moving the face up or down in addition to being slightly off to one side or the other. Of course, in many or these views one ear or the other will not appear in the drawing and other major features may appear differently.
Whether viewed directly on or in one of the other views noted above, what remains primarily is judging the light correctly and shading areas of the face appropriately. Pencil drawings of faces are challenging, but drawings done with colored pencil can also be attempted as well. There are many internet sites that can be very helpful in mastering the challenges of drawing faces. Some of these are noted below: http://www.artyfactory.com/portraits/pencil_portraits/pencil_portrait_1.htm http://www.how-to-draw-and-paint.com/how-to-draw-faces.html