What can a writer do to surprise readers in a story? •create a plot twist that affects the story's outcome
•speed up the narrative progression
•have the story continue to progress at a predictable rate
•slow the story down and add more detail

create a plot twist that affects the story's outcome

Explanation:

The readers will be surprised about about the plot twist and then it will create tension and rising action. But, also because then people would start wondering why there was a plot twist. And the readers would never see it coming.

I hope this helps.