Because the question period comes at the end of your speech, it's important to do it right and leave the audience with a good impression. Follow these tips to ensure your organization doesn't lapse during this period:
Announce both at the very beginning of your talk and at the start of the question-and-answer (Q&A) session when you are going to take questions. You can also tell your audience that you will cover topics only related to your talk and subject.
Don't give a set amount of time for questions—that way you can stay flexible and if you really run into trouble you can get off the hook by saying, "I'm sorry, we seem to be running out of time."
Remember to keep the final minutes of a speech for yourself. They are the prime time; why turn them over to someone else? Whether you're concluding with a summary or some provocative, additional food for thought, prevent a messy ending by asking for questions before you present the real conclusion of your speech. A simple statement like, "I'll be happy to answer any questions you may have, but I would like to hold the final two or three minutes for a summary," will keep you in control.
Those few extra moments at the end will also give you a chance to recover from any irrelevant or awkward questions, and send the members of your audience home with your ideas on their mind, not someone else's.
Stay flexible. If you happen to get a great question that ties in perfectly with your speech, by all means use it.