When a basketball player pivots, he keeps one foot in place while spinning to the side to change direction.
That’s what a plot twist does.
The story’s new direction doesn’t come out of nowhere. It’s rooted in the overall context of the story, but it takes everyone by surprise.
Also, the momentum that appeared to be moving the story in one direction actually propels it into a new, even more meaningful one.
Look for ways to make every scene pivot away from expectation toward satisfaction.