Here are my notes from Tom Shannon, the instructor, he was incredibly knowledgeable and interesting. He worked for Disney a lot.
The mouth is an emotionally indicator. Eyebrows help indicate emotion.
The eyes are the thermometer of what kind of character. The eye is complicated in cartooning it is reduced to a graphic symbol. The lines around the eyes are useful tools.
The chin can hlp indicate character.
The nose helps turn the head. It doesn't indicate emotion but it does indicate direction (where the head is pointed). Every nose is different. The hair moves away from the head. Different chin lines can help define the character. Cartooning is an abstract art.
It's easier to draw the head as a basic circle because it's easy to move. All you have to do is move the nose. Make the circles round and don't draw very dark. Draw right away it keeps you from "white paper syndrome."
You can do anything in a cartoon. Age can be shown by hairstyle. Remember when you are cartooning you have a lot of power you can literarly move mountains. When drawing a hat connect it to the head. The mustache is a vehicle to wrap around the head.
Look at your drawing as a whole. Try to move the pencil around. Keep a generalized notion - like a conductor or an orchestra. Don't focus on one thing.
1. Gesture, Pose
2. Emotional, Facial
3. Construction of Character Itself
4. Background (credible platform for the character to be standing on)