Here's the exercise from the Preston Blair book that I did before I produced my "Helloooooo...." animation. Notice where I've made corrections in red. It's amazing how even the most subtle change can effect whether or not the sound matches the image. Knowing these facial expressions ahead of time was a real help, but I still found myself looking in the mirror to see just how the face contorts when you form the "wuh" sound, or the "heh" sound. Try it - it's fun! And the best part is, the only person you've got to embarrass is yourself.