When we think of expressions, we often think of the features: Cranky eyebrows, gritted teeth, a sheepish grin, etc. What we don't always think about is the shape of the head itself. The shape of the head, its form and structure, can literally be stretched and pulled to make different expressions. This is such an effective method of creating expressions that sometimes I'll draw the distorted head shape first, before the features are even completed. To stretch the features, think in terms of specific forces pulling on different parts of the face.
You can use this pupster for practicing your drawings.
Best-Selling Author Christopher Hart has over 3 million books in print, in over 20 languages. He is published by Watson-Guptill, the art imprint of Random House. You can see him on the Comcast TV Network, where he hosts segments, “How To Draw Action Heroes With Chris Hart,” on The Activity TV Channel.