What Are We Looking For?
A story is ready to ship when the back story has been fully explored.
How do you know? You don’t, really. It’s a feeling that comes from accepting that all of the angles have been covered to the best of your ability. If there is still an issue that you see can be raised, a question to be answered, you are not done.
Readers are distracted by lax storytelling. Convenient events or plot holes can ruin the experience.
The story is ready to ship only when, after giving it time to rest, you can read it and wonder just how you did it.
That is the sense that will engulf the reader. That is what we are looking for.