“Show me; don’t tell me.” It’s something beginning writers are told over and over again, and it’s good advice. It’s not enough to hear it once, though; you have to remember it every time you sit down to write. Otherwise, if you’re writing about three people in a room having a discussion, you might start with something like this:
Joe said that he felt Sam was defrauding him. Sam didn’t like what Joe said, and Bill was sitting there thinking that everybody was losing time.
There are two problems here, and they’re related: you’re telling, not showing; and you’re head hopping—you’re telling the reader what’s going on inside each of the characters’ heads. There’s no reader involvement. But if you work with a single character’s point of view—say Joe’s—then you can only describe what Joe can see. So maybe he says he thinks Sam’s defrauding him, Sam fidgets uncomfortably in response, and Bill shifts from foot to foot. Now you’re getting somewhere: you’re showing readers what’s happening instead of just telling them about it.
Point of view goes hand in hand with the idea of showing instead of telling. Each time you’re writing a scene, you have to make a decision about whose point of view to use. (By a scene, I mean a particular set of events that occurs in a single setting without new characters coming or going.) You can think about scenes in your book in much the same way as scenes in a movie: you can see emotion in the actors’ facial expressions or the way they shift their weight, so you don’t need anyone to tell you what’s going on in their heads.
Of course, if you’re writing in the first person, you can only ever use the narrator’s point of view. Maintaining a single point of view forces you to show instead of telling, because you only have access to what one character is thinking. All the other characters’ thoughts and feelings have to be shown by their actions. But most popular fiction is written in the third person, so you have to make a decision about whose thoughts the narrator has access to, and it’s usually best to limit that access to just one character in each scene. Of course, sometimes that won’t work. For example, maybe you have a scene in which a married couple is having an argument, and you’ve been telling the story up to this point from the husband’s point of view. At some point, you want to switch to the wife’s point of view to achieve a particular effect. You can do that; you just put in a couple of line spaces and then pick up the narrative from the wife’s point of view. But you can’t just switch back and forth throughout the scene, because as soon as you do that, you’re telling instead of showing. Telling, unlike showing, leaves nothing to the reader’s imagination, and imagination is what pulls the reader into the story. Without that pull, there is no dramatic tension.