1. Over-practice your talking points. This will reduce the likelihood of you being tripped up when facing an unexpected question. If not on-the-air (before a live audience) and you're unsure what to respond, turn the question back to the audience by asking, "What do you think?"
2. Don't have long pauses before answering a question. Nothing sounds worse than "dead air."
3. Don't tell the host that they're wrong no matter how idiotic their remark. Remember that they control the microphone so always be (tactfully) praising ("That's right, also...").
4. Don't tell stories or jokes with a religious or political element. What seems innocuous to you, can offend a stranger.
5. Despite your anxiety, force yourself to speak S-L-O-W-L-Y.
6. Look about your audience as you speak, focusing on different members if before a live audience.
Be optimistic since public speaking can be enjoyable for it provides a natural "high" after receiving the attention of many.