But some of it has been observing extroverts interact with one another and learning their conversational protocols. A lot of people take not-interrupting as a signal to continue endlessly, and are perfectly happy to be interrupted if done in certain ways.
Adopting their protocol never feels perfectly comfortable to me. But, then, neither does trying to figure out how to fake a heart attack so I can get out of somebody's monologue.
So you might try watching your brother with his friends and see how they manage to get heard and/or not kill him.