The goal of a debate is to win, to convince the other side (or an audience) that you are right. Debates are arguments, you vs them. If a debate is to be meaningful and productive it has to begin with understanding. 

If the goal of a debate is to yell, criticize, and get angy then jump right in. If the goal of a debate is to learn and to find best solutions then debating is not the first step.

Before debating, people need to first understand each other. What belief system are you coming from? What are your values? What are you goals? What are you concerns? Why do you think this way?

Only after the two sides understand each other can a productive debate begin.

Presedential debates are stupid and pointless. Presedential debates are two ass-hats arguing without listening.