And in Improvisation there is one hard and fast rule, and that rule is known as "Yes And." The term YES AND: to say yes, and not just yes, but to add information. In the adding of information you don't negate the other persons idea - but you build on it.
Maya RudolphWhen I first moved to New York, someone who thought they knew more than I did said: "You have to always look like you know where you're going when you get out of the subway."
Maya Rudolph