Step one, spend an untold amount of time pouring your soul into your book.
Step two, reach in with both hands, grab a big hunk of words, then yank them out and throw them away.
When your novel is 112,000 words and no one will read it over 100,000, you can either leave it as is, your pride and joy, your child, and keep art for art's sake. Or you can strip it down, sell out to "the man", give in to commercialism, trade in your artistic roots and make the darn thing salable.
That is your choice. Good luck!
The idea just came to me. I had a great climax to my book. And after the climax came another chapter that kind of dragged, and then the big finale. The problem is, readers might get frustrated that the book didn't wrap everything up during the climax. It left loose ends that took another 30 pages to finish.
Sure those 30 pages were fun. Sure, they had imagery, excitement, drama, you name it. But when it's time to go, it's time to go. And no matter how good a book is, the reader is ready to check out and be done with it when the rhythm of the book tells them "this is the great, final end-game, and all questions will be answered in this wonderful scene".
When it drags on after that, people tend to lose interest.
So, in the interest of holding interest, I am going to cut the last 30 pages from my book, rewrite things a bit, and see if that makes it more energetic. I'd rather leave them wanting more than to give them more than they wanted.
This is the writing process, this is what writers have to go through to turn their work of art into a lean, mean publishable machine. I am selling out to the man. That is my mission. But it will be a better book because of that.