Write down the basic facts: date, time, place, who, what, when, where, why, then call.
Speak slowly and distinctly. The general public is really stupid.
Avoid controversy and change subject always to what you are going to accomplish.
I do it here locally with a great talk show host. Yes, I was scared at first but after the first 15 seconds and you get in the flow, it is easy.
One more tip. Make your point, shut up and breath, it is time to think ahead.
Good luck Freeper Hobsonphile.