Divide the opening parts of a book into small chapters. This way, you keep a fast pace, allowing and encouraging the reader to quickly complete one chapter and then move to the other.
Keep a conversation or an action sequence within the same chapter, to help readers follow the flow of the story. A reason to divide it is to provide a cliffhanger.
Alternate between high drama chapters and more relaxing ones for the reader. For instance, after a wild chase, the next chapter can be about the hero relaxing while hiding. On such occasions, ensure the dramatic scene has de-escalated before the end of the chapter.
Change chapters when the point of view is altered or divide the chapter into separate parts. There must never be more than one narrator within a chapter without some sort of clarification, such as different fonts or clear subdivisions. Otherwise, readers can easily become confused.
Stress highly important sequences by dedicating a chapter for them, no matter how short. However, the size should be more than a single page. This is especially helpful when you want to isolate the climax of the story.
Assign a number or a short title to each of your chapters. Numbers can help readers remember where they've left the story, while titles can also give a small glimpse of what they should expect in the following pages.