I'm from a copywriting background. One of the "tricks" we're taught to get better at writing fast is to physically hand-write successful pieces (sales letters) over and over. I'm guessing there's a science to it. Maybe something to do with muscle memory. I think it was first suggested by Gary Halbert, something of a titan in the direct response industry. (He's since passed.) I did it for months. While monotonous, extremely boring, and time-consuming, I have to say it worked wonders. I started to realize what the pros were doing. How they were overcoming objections, the techniques they were using, the specific structure they followed, and so on. I remember Gillian Flynn talking about this in one of her novels. I've never tried it with a work of fiction. Have you tried it or heard anyone talk about it? How did it work out for you?