I always love it when I find posts about how each frame of your animation is important. After my rant about how you should not be your computer's slave, make sure to read these two awesome posts over at the Midnight Diaries of Catty Wampus:
"Every frame is a drawing."
"back and forth: an animation tip"
When you move from one pose to the next, nearly every single body part should move, even if it’s only a little bit.