Oftentimes, a work-in-progress will contain an empty space that you'll later need to fill

This is a difficult idea to articulate, but I'm going to give it a shot. I'm in the process of revising a novel right now, and I'm in that part of the revision process where I sit back and try to figure out what exactly I need to change. It's a pretty holistic process: once I decide that a book needs to be revised, everything becomes up-for-grabs, and I…