Truthfully, you probably don’t. If you are fortunate enough to have a publisher or agent waiting for that next great American novel, the letting go may be just a little easier. If you don’t have a publisher or agent giving you a deadline, give yourself one.
We write the first draft, we polish, second draft polish again . . . and on and on. By the time you have polished the third time, take a break away from it. Shove it into the farthest corner of your pc (or your mind) for at least a full two weeks- maybe more.
When you come back to it, look for credibility issues. Is your story believable? Does it have compelling storylines and interesting characters? Remember, the reader may not share the vision in your head. I have had my characters so fully formed in my mind that I did not notice they were paper cut-outs on paper. Have someone else read your manuscript start to finish without giving them your views. Let your beta reader enter your story world unbridled by your opinions and concepts of the story. If he/she can’t understand the theme, you are not done.
Then, with fresh eyes come back to it again and see if there is something that blatantly stands out as an error. If so, go back to the drawing board and fix them. However, if you only picking lint, let it go. When you get that agent or publisher, their editor will pill the wool. It’s not your security blanket (or sweater). If you are self-publishing, now is the time for that all important editor. Perhaps you hire one privately. Perhaps the publishing company you have chosen for your Indie publishing has an editor. Don’t skip the process.
Finally like letting the bird leave the nest, let it fly. Give it permission to soar. Give it your blessing and stand back. Well, not exactly. Now you have to start to market. But that is a whole new blog.
How do you know when you are done? When do you let go?