Handling Q&A
Most conferences request that you leave some time at the end for Q&A.
There are several things you can do to handle this time with aplomb:
0. Ask for questions the right way.
Don't say "any questions?" Say "let's have some questions!" The subtext of the first is that you should ask a question if you didn't understand something.
People are reluctant to admit they didn't understand, or to imply that you didn't explain something sufficiently. The second form shows that you EXPECT questions, and don't plan to finish until some are offered up. The difference is subtle but important.
1. Shut up and wait.
After you say "let's have some questions", you MUST shut your mouth and wait silently.
Every audience in the world needs about around eight seconds before someone will venture a question. People need time to think of a question, work up the nerve to ask it, to look and see if they'll be interrupting anyone, etc.
These eight seconds will feel, to you (and only you!) interminable. Don't try to hurry it along with encouraging comments, just smile, try to look comfortable, and wait.
The good news is that after the first question, you'll usually get a few others with almost no delay.
2. Repeat the question.
Unless your venue is set up with mics for the audience, you'll likely have people yelling questions across a crowded room. In this scenario, always summarize the person's question before you start answering it.
This is mostly to make sure that everyone heard the question, but has the side benefit giving you a chance to confirm you understand the question: "so the question was whether emacs users should be ostracized or simply ignored, is that correct?"
3. Answer honestly and don't get defensive.
The Q&A period is much different than the portion of you just talking because you don't know where it's going to go. You're likely to get questions to which you don't know the answer. Admit you don't know and do your best to point the questioner in the right direction.
During Q&A you may have someone point out that you said something inaccurate, or missed pointing out something useful. Accept this sort of feedback happily.
If you made a mistake, admit to it immediately. Being totally honest will win you more credibility than pretending to be right all the time.