We are wonderfully made.
Portraits, caricature, drawing faces, photographing faces, all have one thing in common. Our facial features. All our facial features are the same. We have eyes, mouths, ears eyebrows, nose and other little oddities such as facial hair and maybe some unique beauty features.
A Child has a shorter face because of the jaw not being fully developed. This is why the child has a larger forehead and the eyes are lower in the face. As the child grows, the chin grows, and the face become longer. The eyes adjust and give the face a more mature appearance. Bones become denser. So the child will have a narrow neck and smaller limbs and so forth.
So how can we use this information as we draw a face. The top of your ears start at the lower part of your eyes. The bottom of your ears come down to the bottom of your nose. Now this is approximate as depending on the size of them. I have very small ears. So you will notice the elliptical line that is dissecting the upper diagrams of the simple faces that this can help you to gauge where you should put the ears. So when you are drawing a face it will help you to map out where everything goes. Also if you are drawing a child, the length of the chin will determine the age.
I hope this will help you to develop you portrait drawings to look more like a face. Especially when you are cartooning or drawing without the face in front of you. Sometimes you will look at your drawing and wonder what is wrong. Well this will help.
Have Fun and remember practice, practice, practice, that make perfect.