Director Satoshi Kon (Paprika, Millennium Actress, Perfect Blue) describes his experiences as a director in an online interview for a feature in the magazine "BusinessWeek".
How I brainstorm differs with every new project. There's no formula. Since there's no telling when or how I'll arrive at my next idea, I have to remain attuned to what's happening around me. I rarely start off with a fully realized vision of a story line. Often I'll have an idea that needs to be fleshed out, and as I proceed a lot of factors will suddenly come together, like a chemical reaction, to form a story line....
....I never imagined I'd become an anime director. At one point, I wanted to make a living drawing manga [comics]. That led me to animation. But I have no idea where this will take me. Some chance incident may change the course of my life, and I prefer to remain open to that. I'm not ambitious. I don't have a dream. I just want to enjoy my work.