Use color , don't mumble. How to make it special, how to illuminate it. As an actor be a chef, be decorative. Any line can be said a thousand ways. Behavior is more important than dialogue .
Radio is dead.
Can't think the story , can't think dialogue . Clarity of words that is what writers want, allow the dialogue to come out, don't disappear. Dialogue are only noises we make. We don't mean what we say. Understand the audience.