Yup, I have been. Both in high school and in college. I LOVE the art of debate.
The first thing you need to do is know the opposing view as well or better than your own. Know what their main points will be and what your counters will be before you walk in. Know whether their arguments are based in logic or emotion.
Next, remain calm. At all costs, remain calm. That doesn't mean that you can't raise your voice or interject some emotion into your presentation, but on the inside you need to be cool as a cucumber to keep sharp.
And the most important thing to understand is that you are NOT trying to convince your opponent of anything. You are trying to convince the audience. The audience is always your audience, not your opponent. He or she is simply a prop you use to make your points.
