The simple outlining technique that helped J.K. Rowling become the world’s first, and so far only, billionaire author.
The hand written "spreadsheet" that J.K. Rowling drew to plan Harry Potter and the Order of the Phoenix
J.K. Rowling says that great writing is planned first. Yes, you can just start and see where it goes, but the results will be better if you plan first.
Article: How J.K. Rowling Used a Hand Written Spreadsheet to Map out the Plot of Harry Potter