|PRINCIPLES OF ANIMATION
Some animators like to get up out of their chairs and go through the character's movements themselves, to get the feel of the action. Some do it in front of a mirror, and other do it in front of a video camera and watch the playback to see what they've done. Some animators ask other animators to act the scene out for them and they'll do quick sketches or thumnbails of the action for reference later.
Whichever technique you decide to use, you need to use your observational skills.
This goes for designing as well. It's pretty hard to draw a cow from memory if you haven't seen one in a while. You could draw from your memory but it's always more accurate to find some reference.
Don't neglect this valuable tool that is available to you if you just get up and use it!