If there's one thing I have learned 23K into my sixth novel, its that not a single book has been written the same way.
My first, my throw away book, was a NaNoWriMo project. I'll be honest and it was more about meeting the goal than the story, although I didn't believe that at the time. I'd started several novels before and never even hit 20K so completing a book was at the top of the priority list. One key for me in completion is that I'd spent a week or so plotting, which had always been my bane. As weird as it sounds to most writers, my blog posts on my family blog taught me to plot. Every blog post/story had a beginning, middle and an end. It sounds logical enough, but I when I started my previous novels-- the unfinished ones-- I had a vague idea and started writing.