One of the bigger problems that comes with writing a book is that of structure. Writers are constantly battling with the reveal of information. In books such as Gone Girl by Gillian Flynn, the reveal of information is incredibly important, as this is where the tension in the book lies. In films such as Memento by Christopher Nolan, the same conceit is true. The structure of a book is incredibly important.
The simplest way to think about structuring a narrative is to think of it as the Beginning, the Middle, and the End. In other words, this is referred to as the three-act structure: the Setup, the Confrontation, and the Resolution. Most films, books, and shows will follow this structure, as it is the simplest tenant of story-telling. Characters need to be setup, a confrontation needs to be introduced, and there must be a resolution. (a note: not all narratives fit so easily into this, as some creators will stray away from the structure)
The beginning of your narrative should set up the characters, the relationships they have with one another, and the introduction of the central conflict of the narrative. So, for example, a murder mystery will perhaps start the book with the murder of a character, set up the lead detective and their relationships to family/friends, and introduce the two to one another. It’s important here to begin laying down the foundations, and not to be too loose with the information. Though you want to make sure that you are providing enough information for the reader to connect to the characters and what is happening, to overload them with information can have the opposite effect.
The middle of your book is where most of the action will take place. This is where the conflict will come to a head, and where the characters will meet one another. To continue the example of the murder mystery, this is where the lead detective will come across certain clues that might lead them to find the killer. However, the killer will most likely evade capture and find out more about the lead detective’s life, using information about their personal details to create tension. It is important here to make sure that the plot is kept tight. Things that do not advance the plot need to be cut from the narrative, as this will make the book appear bloated. It’s easy to want to show off a character by adding in extra scenes, but if these do not advance the plot, then it can be easy for the reader to turn off.
The ending of your book is where the final meeting between the main character of your book, the protagonist, will meet the villain, the antagonist. Here, the tension that you have been building throughout the narrative will come to a climax. In the murder mystery, this is when the lead detective follows an anonymous tip without backup to find that the anonymous tip came from the killer. They meet, they fight, and the killer is killed, but not before there is a moment when there is a possibility the killer might kill the lead detective. The narrative will then come to a resolution, where the characters accept what has happened and their character arc is closed.
It is important to note that some narratives won’t follow this setup, and will deviate it from it, but as a general stance, most narratives tend to fit within these three stages.