Answer, Add, Ask
My tutor told me a basic principle of small talk: "Answer, Add, Ask." Which means that once you take the the ball from him, respond to it with extra information (Answer, Add). And then, after a short pause, give the ball back to the opponent(Ask) in order to show you are interested in trying to keep a balance of total amount of conversation between you and him. It is OK if he speaks more than you, but the opposite is not good.