Anticipate questions beforehand. If you work at it, you can predict nine out of ten of what you'll be asked.
Rehearse the answers with your experts present. Know your facts are right before you go live.
Always restate or rephrase the question. Not sometimes. Always.
Identify the issue at the core of the question. Rephrase on the issue.
Think about the answer until you have rephrased the question. If you do that, the answer will be there.
Answer back by directly addressing the questioner. He or she will trap you with another question, and another. You want dialogue, not monologue.
Think you can wing it without rehearsal. That's hubris. You gain nothing but could lose everything.
Try to put down a questioner. If you're successful, the audience won't forgive you. If you're not, they won't forgive you. Either way, you lose.