Are you a pantser? Someone who doesn’t outline their story, or at most partially outlines it. I fall into the latter category.
My current YA novel started life as a 250-word flash mystery story submission to a pulp magazine. It was a runner-up, and I liked it, so instead of lengthening it some and submitting as a short story, I decided to use it as part of a scene and build my novel around it.
I didn’t try to blow that story up to become the novel, but instead to use it as a seed. It turned out to be around one fifth of Chapter 3.
Since I had designed the character and given her the attributes I wanted in the short-short story format, it was an easy task to write the first few chapters, and create a suitable ending. Doing it that way made it a lot easier, since I knew exactly where I was going.
The novel has been through its first pass with an editor and sits at a little more than 55,000 words. A decent number for YA.
Let me know your method.