Sometimes we forget that conversations are a two-way street.
The best way to fight the urge to slip into monologue mode when in conversation is to practice active listening and ask questions.
First, LISTEN. When others speak, try to visualize what they are saying. Give affirming head-nods and focus as they speak.
And rather than try to think of what YOU are going to say next, think of a question that gets the other person to continue to open up.
Remember to talk WITH people, not AT them.