Don’t dither. Avoid weak, throat-clearing closes, just as you’d avoid throat-clearing, inconclusive openings. Let the ending be the ending, without waffling afterthoughts.
All the subordinate characters possible should be shuffled offstage, their work done, as the ending approaches, to leave the major characters alone in the central spotlight.
Settle the important things—not everything…Just as good openings start in médias res, with something already in progress, good linear endings don’t wait till every bit of the dust has settled.
Most important of all, though: don’t introduce a new plot. Stay with the main plot.
– Anson Dibell, from Plot: Elements of Fiction Writing