I’m in the midst of the first book in my new series (The Affinities of Magic), and it’s a very different writing process from my previous book, which was the fourth in its series (The Hounds of Annwn).
I’ve gotten to know my primary characters in the older series pretty well. I know what they would and wouldn’t do, and a good bit of how they interact with each other. In other words, I'm comfortable with them.
In novels of adventure, the sort of thing I write, you need a good story, a sound plot, and it’s a good idea to have the basics of that in your head before you begin writing. Perhaps the details are hazy — maybe you don’t know exactly how certain things are going to happen — but I find I need at least a sketchy outline of the key plot points before I can start. Some authors are comfortable just writing into the void, but I’m not one of them. (The lessons of Wile E Coyote are all too vivid.)
Plots in and of themselves don’t scare me. I used to be a serious software engineer, and what is that but the instantiation of a fully realized product where all consequences are knowable (at least, after debugging).
But story comes from characters, and that’s my current sticking point. Who are all these people?