You have to follow [a question] through production, post-production, and then some. If you can ever get into something and have it all figured out, then you probably shouldn’t make a film about it. Then, you’re done.
This before all: ask yourself in the quietest hour of your night: must I write? Dig down into yourself for a deep answer. And if this should be in the affirmative, if you may meet this solemn question with a strong and simple, I must, then build your life according to this necessity.
Ideas can come from anywhere, they are the vital spark that starts the writing process. One of the best ways of deciding whether you’ve got a good idea fora movie is to ask yourself one simple question: “If someone else had written this story, would I get on a bus, go down to the cinema and pay to watch it?”