The short (and smart-ass)answer is "at the beginning".
But that's not what I'm going on about today. No, I'm speaking of that most sacred cow of questions that new writers have for the pros; How do you WRITE a novel? A question that any writing pro SHOULD tell you has no direct answer. Anyway you want, is the answer I like.
There are endless creative processes to choose from. Some have to have every detail laid out in stacks and stacks of character notes and a rigid outline before anything is committed to paper. Some have whiteboards on the walls of their office with major charcters listed and track each character's progress in the story with a flow chart. A few brave souls have the raw talent to just go to town without anything more than the idea for the story. Myself, I can't micro-analyze to that degree but having some sort of roadmap is very helpful.
For my novel, I guess I could say I'm in the outline stage (and I use the term loosely). I went through a period of making some character notes a couple a few months ago. While letting the idea, and the things I planned for it, congeal into something more useful, I spent time writing short stories. After mulling things over in my head from time to time, I felt like that pie was fully cooked which brings us to now.
My "outline" is, basically, a bulleted list of events I envision for the story. I've done this before. A couple years ago before SNW, I had an idea for a Star Trek novel. Back then, I knew very little about the writing profession. I figured everyone was a heavy outliner with endless rewriting over and over and over. The thought was intimidating and I knew I didn't have the discipline for all of that at that time. I decided to try to keep things simple and started the list. I found that to a degree this list was writing itself. If THIS is going to happen then THAT has to happen. Things began to show themselves and link up in a logical progression. I completed the "outline" for that book, but never wrote it. S&S's policy about not accepting unsolicited manuscripts didn't sit well with me.
Anyway, the list is coming together pretty well. I find it easy to see holes that need to be filled. The neat thing is, some of the things in a list like this can be moved around, like chess pieces, to make the story flow the best way possible. This method could have a benefit later. If it's good and clean enough, I think it will be handy in writing my synopsis for that first agent the requests a partial.
I esitmate I'm about halfway through it at this point. Then it'll be 1000+ words a day until completion. I'm projecting 80,000 words should serve this story nicely.