I'm sure you have, but if you haven't, check out Stephen King's book On Writing: A Memoir of the Craft. It's really one of the best books out there on the process. A real master class in the craft.
I'd read it many years ago, and last year I decided to download the audio version. It was great. The author reads it himself, and his conversational tone gives the impression that he's sitting across the table from you.
King not only talks about the his process, but he also discusses the rejections, his long road to success, and also the accident that nearly ended his life.
It's definitely worth a read or a listen.