Nothing will take you out of a story faster than bad dialogue. If someone is reading your dialogue and thinks, “I’m reading dialogue,” you’ve lost as an author.
Poorly written dialogue is like looking through the mouth hole at Disneyland and seeing the person inside of Mickey. The magic is gone when the mechanics are exposed.
So, how do you avoid writing Mickey-mouth hole dialogue? The first step is to listen to people talk. Be an observer. Listen to your friends banter. Listen to strangers in line for coffee ahead of you. Listen to your co-workers talk shop. Get a sense for how real people communicate (learned this from my friend Lance: people are much more subtle than we write them).
Another way to test your dialogue is to read it out loud. Act it out. If you fumble over the words or sound like a robot, you know that line needs some love. (side note: I recommend doing this when you’re on the second or third revision, NOT while you’re writing the first draft.)
It’s a time-consuming process to read your dialogue out loud, but your book will be better for it. And, after all, that’s what we all want, right? The best written book possible.
Jump. Build, Fly.
F.C. Shultz