Each chapter is a mini story in its own right, so to work properly, just like any story, each chapter must have, as a bare minimum, a beginning, a middle, and an end.
Or to put it another way every chapter needs a three line plot. This consists of:
- A premise – what is the scene about.
- A complication (one per scene) – (But) what difficulty do the characters have to overcome and how do they overcome this complication.
- A trigger – How overcoming the complication triggers the next complication that needs to be overcome in the next scene.
Each chapter may be a single scene which follows a simple story arc, or may comprise of several simpler scenes, each with a beginning. Middle, and end, that together form the story arc. I prefer to use a variation on the classic eight-part story arc.
However, unlike the overall Story Arc, most chapters do not end with a Resolution, but with the trigger for the next scene in the flow of the story. This keeps the story moving and the reader turning the pages. The trigger would normally by a consequence of the complication or difficulty tackled in the scene/chapter. If it is the last scene in a chapter, then classically the trigger could be a cliff-hanger to the first scene in the next chapter or the next scene involving that character.
Here is a Scene Flow infographic from my article on Creating Good Scene Flow that applies equally well to structuring chapters.