One of the first lessons you must learn as a novelist is the difference between the way people actually talk to each other in day-to-day situations and written dialogue that sounds real. Some might think this notion is self-contradictory; after all, if a character is speaking the way people speak, isn’t that the same thing as sounding real?

Not by a long shot. First of all, think about the last conversation you had with someone—say, over coffee at the office. Most of us give our normal, unrehearsed conversation a liberal sprinkling of “uh,” “you know,” “so,” “I mean,” and other such expressions that don’t really mean what their dictionary definitions suggest (if they even have a dictionary definition). Not only that, but in real conversations, people start and stop mid-word, use sounds, facial expressions, and body gestures, and a host of other communication techniques that are so habitual, most of us don’t even realize we’re doing them.

By contrast, good dialogue in a novel has a single function: to move the plot forward. So, unless it’s an important plot point that a character habitually avoids the topic at hand by talking about the weather, the paint on the wall, or other such things, having that sort of stuff in your dialogue doesn’t serve the story you’re trying to tell.

Here are a few rules for writing good dialogue. There are many others—probably as many as there are different writers. But these are tried and true, in my experience.

1. Real dialogue gets to the point. It doesn’t use a conversation as an excuse for giving the reader a history lesson or a lengthy exposition. Real dialogue carefully considers what the characters in the scene know, what they want to know, and what they are willing to reveal, and it sticks to that. If you read dialogue that runs page after page—especially if one character is doing most or all of the talking—you’re probably reading plot exposition or backstory disguised as dialogue. You’re probably also getting bored and thinking about putting the book down.

2. Real dialogue recognizes that different characters have different patterns of speech.Please don’t confuse this with attempts to represent colloquial or ethnic speech with made-up contractions and tons of apostrophes to represent dropped consonants—that kind of writing went out of style decades ago and is now typically seen as demeaning. But word choice, rhythm, short vs. long sentences, and other characteristics of speech vary from person to person, and good dialogue recognizes that.

3. Show, don’t tell.As I’ve mentioned previously, this is a prime tenet of good fiction writing, and it also counts in dialogue. When a character launches into a lengthy explanation, that can be an indication that the writer is telling instead of showing. Just because you put the telling in a character’s mouth doesn’t transform it into showing.

4. Not all dialogue is in words.Sometimes, a well described facial expression is ten times more effective than the character saying what’s on her mind. Sometimes a character’s silence speaks volumes.