I have a lot of the story worked out, but so much of it is serendipitous as I'm writing. Write your own vision and don't let people tell you what to do. It's the discipline and doing the craft. Not waiting for the inspiration, but writing even when you are not feeling particularly inspired. You get your ideas from doing it, not from thinking about it and then sitting down.
Inspiration counts for very little.
What you want to do in any creative field is find your own voice, your own style. You don't want to paint like Picasso, you want to paint like yourself. You want your type of work to be in your own unique voice. Now, of course, you'll always get remnants of styles because of who you like, but if you don't find your own way of expressing yourself, you are going to be in big trouble. Many people want to know how you manage to juggle the egos and the working schedules of two New York Times best-selling authors, as well as a busy household.