Show your piece to a number of people—ten, let us say. Listen carefully to what they tell you. Smile and nod a lot. Then review what was said very carefully. If your critics are all telling you the same thing about some facet of your story—a plot twist that doesn’t work, a character who rings false, stilted narrative, or half a dozen other possibles—change that facet.
It doesn’t matter if you really liked that twist of that character; if a lot of people are telling you something is wrong with your piece, it is. If seven or eight of them are hitting on that same thing, I’d still suggest changing it. But if everyone—or even most everyone—is criticizing something different, you can safely disregard what all of them say.
In the same piece, King advises “if it’s bad, kill it.” (“When it comes to people, mercy killing is against the law. When it comes to fiction, it is the law.”)
1. http://www.jerryjenkins.com/guest-blog-from-stephen-king/