A Prayer for Rain on Sukkot - What Are You Said to Do?

In the land of Israel, it really doesn't rain until Sukkot. That's when you start asking for the rain. And what happens if the rain doesn't come? Of course, the rain is the main source of your food. So a drought is not just an inconvenience. It's really a main threat to your survival. The law that we're going to look at is what are you supposed to do in a situation of drought?