I thought I had this somewhere on the site already. Seems not. Here it is:

Pixar's 22 rules of storytelling:

• You admire a character for trying more than for their successes
• You gotta keep in mind what’s interesting to you as an audience, not what’s fun to do as a writer. They can be very different
• Trying for theme is important, but you won’t see what the story is actually about til you’re at the end of it. Now rewrite
• Once upon a time there was . Every day, . One day . Because of that, . Because of that, . Until finally .
• Simplify. Focus. Combine characters. Hop over detours. You’ll feel like you’re losing valuable stuff but it sets you free
• What is your character good at, comfortable with? Throw the polar opposite at them. Challenge them. How do they deal?
• Come up with your ending before you figure out your middle. Seriously. Endings are hard, get yours working up front
• Finish your story, let go even if it’s not perfect. In an ideal world you have both, but move on. Do better next time
• When you’re stuck, make a list of what WOULDN’T happen next. Lots of times the material to get you unstuck will show up
• Pull apart the stories you like. What you like in them is a part of you; you’ve got to recognize it before you can use it
• Putting it on paper lets you start fixing it. If it stays in your head, a perfect idea, you’ll never share it with anyone
• Discount the 1st thing that comes to mind. And the 2nd, 3rd, 4th, 5th – get the obvious out of the way. Surprise yourself
• Give your characters opinions. Passive/malleable might seem likable to you as you write, but it’s poison to the audience
• Why must you tell THIS story? What’s the belief burning within you that your story feeds off of? That’s the heart of it
• If you were your character, in this situation, how would you feel? Honesty lends credibility to unbelievable situations
• What are the stakes? Give us reason to root for the character. What happens if they don’t succeed? Stack the odds against
• No work is ever wasted. If it’s not working, let go and move on – it’ll come back around to be useful later
• You have to know yourself: the difference between doing your best & fussing. Story is testing, not refining
• Coincidences to get characters into trouble are great; coincidences to get them out of it are cheating
• Exercise: take the building blocks of a movie you dislike. How d’you rearrange them into what you DO like?
• You gotta identify with your situation/characters, can’t just write ‘cool’. What would make YOU act that way?
• What’s the essence of your story? Most economical telling of it? If you know that, you can build out from there