Pixar’s rules of story

• Empathize with your main character, even if you don’t like all of his/her motivations or qualities. (For example, Woody in Toy Story initially masked his selfish desires as being selfless.)
• Unity of opposites. Each character must have clear goals that oppose each other.
  You should have something to say. Not a message, per se, but some perspective, some experiential truth.
• Have a key image, almost like a visual logline, to encapsulate the essence of the story; that represents the emotional core on which everything hangs. (For example, Marlin in Finding Nemo, looking over the last remaining fish egg in the nest.)
• Cast actors with an appealing voice, and whom the microphone loves. Test their voice performance with animation to see if it fits.
• Know your world and the rules of it. (Such as in Monsters, Inc.)
• The crux of the story should be on inner, not outer, conflicts. (emphasis added)
• Developing the story is like an archeological dig. Pick a site where you think the story is buried, and keep digging to find it.
• Animation should be interpretive, not realistic.
• “Just say no” to flashbacks. Only tell what’s vital, and tell it linearly.
  Consider music as a character to anchor the film. Music is a keeper of the emotional truth.

Don’t know how true this all is. Found it here.