A chapter’s ending is likely where a reader will take a break from reading. Ideally then, chapter endings need to encourage a reader to return as soon as possible. There are three useful ways in which this can be achieved: intrigue, danger, or through revelation.
Creating a sense of danger is clear enough, as the writer simply implies a risk of harm for their characters. For creating intrigue and revelation, here are two experts for guidance:
Karl Iglesias on intrigue:
Create intrigue by emphasizing illicit activity and secrecy (Writing for Emotional Impact)
Any time you establish secrets—a secret scheme, a covert operation, a cover-up of information, or an assassination attempt (JFK had it all), it creates intrigue, especially if the scheme is illegal. (Writing for Emotional Impact)
John Truby on revelation:
Revelations in stories are moments of discovery, and they are the keys to turning the plot and kicking it to a “higher,” more intense level. (The Anatomy of Story)
The moment of revelation should have these qualities: It should be sudden (…) create a burst of emotion (…) be new information for the hero (The Anatomy of Story)
Revelation will likely work best after the story’s opening and when the characters and their plight are fully understood by the reader (because the reader needs to first care about the characters in order to care about their situation). Revelation needn’t be grand or life-altering for a character either, although these are certainly some of the most compelling revelations.
Note that these types of chapter endings do not need to be overly dramatic. Here are a couple of chapter endings to demonstrate this point (mild spoilers):
Intrigue: from The Exorcist
Chris again found herself turning worried thoughts toward Regan. She tried to watch television. Could not concentrate. Felt uneasy. There was a strangeness in the house. Like settling stillness. Weighted dust. By midnight, all in the house were asleep. There were no disturbances. That night. (William Peter Blatty)
Danger: from The Lord of the Flies
Roger edged past the Chief, only just avoiding pushing him with his shoulder. The yelling ceased, and Samneric lay looking up in quiet terror. Roger advanced upon them as one wielding a nameless authority. (William Golding)