Well, first I bullet point a ruff storyline, then to create chapters I write down what I want to reveal, emphasize, or achieve in that chapter, for example, the type of relationship between two characters or a certain event that's important to the plot. Then I build on this by imagining situations or events I would like the characters to be part of, like a chase or discovery, and altering it so that it tells the points I want, then I start drafting and pulling everything together, then I polish and polish until I'm happy with it. Also, a good tip is to write your ideas and thoughts down as soon as you have them, no matter how bad they might sound because you may be able to make some thing of them. Good luck with your writing! I hope this helped!! :D