There are two enemies of excellence, and they are two of the enemies of our writing career: perfection (analysis paralysis) and “good enough” (laziness). No book is a perfect “100,” and a killer “95” manuscript (arbitrary scale) on our hard drive is of no more value to our career than submitting an “80” that’s likely headed to the slush pile. I’m very close to submitting my picture book manuscript. I’m just not sure it’s good enough to hit the “90 to 95” sweet spot of excellence, i.e. good enough to be accepted with comments and/or final polishing. It’s been through multiple read/comment/rewrite cycles and two rounds of review and comment by a professional editor, so I’m confident the mechanics, punctuation, and grammar are sound. I’ve read it out-load several times and made little refinements. Now I want to review it one or two more times looking at each verb, “Is there a better one, more exciting, more descriptive?” Are there still sections of narration that could be replaced by action or dialogue? After that, I think it will be time to roll the dice and see what happens. This is the scary moment.
Using a car restoration analogy, you spend a lot of time eliminating dents and lumps, making the surface as smooth as possible. This is emotionally easy because there’s always tomorrow to make it a little better. However, if you want to put the car on the road, eventually you have to cross the point of no return: mix the paint, load the paint gun, and start spraying.
A famous author, I can’t remember who, was invited to join some friends on a weekend adventure. He declined, wanting to work on his latest manuscript. Upon their return, they stopped in to see how much progress he’d made. His answer was something like, “Great weekend. On Saturday I added a comma to the closing sentence, and on Sunday I removed it.” To my mind, this manuscript is ready; he’s revising the revisions.
Bottom line: there’s no pat answer. I think we work on our book until we can’t think of anything else to improve it, or until we can’t stand to work on it any longer. Then we commit an act of faith in our skills... and query/submit. Good fortune!