What does “on the nose mean,” actually? Well, it means the dialogue is so straightforward, so to the point, that it doesn’t sound natural. How can you avoid it? Here’s a little trick that I find really helpful in the early stages of writing a scene. Write the dialogue as absolutely on the nose as you can:
Jane: I hate you and I want to get divorced. Ken: I am shocked and hurt.
Go through the whole scene and just get the intention down on the page. The intention of the characters, their rudimentary understanding and reactions are all you’re going for. Now once you’ve got the scene written in this way, go back, and bearing your characters in mind, soften it a bit. So it might be something more like:
Jane: I need my freedom. Ken: But I love you!
And later, that might morph into something more character- driven and specific like:
Jane: I can’t believe you waited up for me.
Ken: You said you’d be home at ten. Where were you?
Jane: Maybe you should sit down.
Go back through your manuscript and examine each scene and the intentions, motivations and goals in the scene for each character.
What does the character want in the scene? And how do they ask for it? What are they avoiding, pressing for or hinting at? Are these things contained in the dialogue?
Think about this: the thing is never the thing. What in the heck does that mean? Well, it means that people usually relate and interact on at least a couple of levels. Pointing out someone’s tattoo might really be saying “I think you’re sexy.” or it might also mean “I think you’re low class.” Which is it? How does your character really feel in that moment? Vulnerable? Jealous? Insecure? Confident? What's the difference between on the nose dialogue and crisp, to the point dialogue? The difference is one of degree; on the nose dialogue is clunky, clumsy and obvious.
BUT writing on-the-nose dialogue can be a helpful way to move forward in the story. You can use it as a placeholder, then come back to the dialogue and finesse it later.