Some excellent WEBSITES and some books to peruse  to help in understanding nonverbal cues and facial expressions:

•   FACE BLIND 

•   HUMAN EMOTIONS

•   GAINING FACE

•    FACE YOUR FEELINGS (recognizing facial expressions) Henny M. Shore, Editor

•    THE  ARTIST'S COMPLETE GUIDE TO FACIAL EXPRESSIONS  Gary Faigin 

•    MOODGYM

•    MONA LISA's different feelings

•   RESPONSIVE FACE

•    FUN FACES

•   MR PICASSO HEAD

•   SIMON BARON COHEN'S READING PEOPLE'S EYES TEST  (Take this test and see how you do)

•    PLAY A GAME ABOUT HOW ARTHUR'S  FRIENDS FEEL (About Face)

•   MORPHING FUN

•   FACIAL MUSCLES THAT WORK THE NONVERBAL CUES

•   MIND READING - THE INTERACTIVE GUIDE TO EMOTIONS

•   HOW FACES MIRROR EMOTION by Paul Ekman

•   Emotions Revealed: Recognizing Faces and Feelings to Improve Communication and Emotional Life  book by     Paul Ekman

•  Facial Action Coding System (FACS) - CDrom for professional use - Paul Ekman