Consciously I have to tell myself to be quiet. Two ears one mouth.
When someone is speaking we should be listening, not preparing to speak. This seems harder when I’m with people I feel comfortable with or believe I know well. With a stranger, I’m more careful with my words. With family, it seems like I’m thinking as I speak, which is often the case.
Awareness of this is the first step to being a better communicator. Listen, ponder, respond. Not always, but more frequently, and with practice.