It's hard, at some point in a manuscript, to see its weaknesses. As a writer it's hard sometimes to see your own weaknesses. I'm lucky to have an editor who has a strength that is my weakness. One of her strengths is story structure which is always a struggle for me, though I think I'm getting better at it. She has been part of that improvement. Of course I don’t agree with everything she thinks needs work. She wouldn’t expect that. But I’m struck by how many times she’s right. She asks the kind of analytical questions that lead me to plot answers that improve the work.
These kinds of plot questions need to be asked. Not in my first draft since my first drafts are mostly a way for me to enter the story, but in later drafts. Here’s a big plot question (when you’re focusing on that aspect of story): What does this scene accomplish? Just that simple and just that difficult. It’s easy to fool yourself. Well, you might say, the scene reveals my character’s love of meatloaf. But is that really important to the story? If not, even though there’s some good writing in that scene about metaloaf, maybe some very funny and entertaining sentences, you have to consider cutting it. That is very hard, especially when it’s a scene you like and enjoy.
Because we’re writing novels we don’t have to be quite as merciless as the story writer. We have a little room, now and then, in my opinion, to wander slightly, perhaps for humor or to make a general statement about life, but I think my editor’s very smart questions about what is accomplished, scene by scene, to advance the story need to be asked at some point. It’s easy for a story to lose its momentum.