You don’t need to know the purpose as you write, but when you read over something you’ve written, you should be able to point to any given element—be that a line of dialogue, a descriptive phrase, a plot point—and say why it’s there.

As a rule of thumb, four consecutive lines of dialogue is about as much as you want to have without a tag.

Don’t let characters talk pointlessly—they only talk if there’s something to say.

Dialogue doesn’t take place in a vacuum. Dialogue is contradictory, in that it can either speed up or slow down a passage.

Pointing out the emotion in a scene is like laughing at your own jokes.

If there’s true emotional content in a situation between characters, all you do is reveal it.

Just as an effective advertisement or page layout includes a lot of white space, a powerful scene requires immense restraint. Show things as simply as possible.

Jamie’s viewpoint is expressed almost entirely in metaphor: If she was broken, she would slash him with her jagged edges, reckless as a drunkard with a shattered bottle. He’s using physical language, but he isn’t talking about the physical details of the situation. Claire alludes to her emotion and shows it by her actions, but Jamie is thinking directly in pure emotions.

This is why you use imagery when writing about sex; it’s a means both of evoking immediacy and of distilling emotion.