The author can use many things such as sentence manipulation, the addition or lack there of for details, and even building up and tearing down momentum.
An author can control the pacing of a story by changing the sentence structure or how quickly events unfold in a story.
Pacing is a tool used in literature intended to control the speed and rhythm at which a story is told and the readers are pulled through the events. It refers to how fast or slow events in a piece unfold and how much time elapses in a scene or story. Pacing may be employed in order to to show characters aging as well as the effects of time on story events.
