Dear Mr. Magic,
What do you say to someone after a trick when they say, "I know how you did that." or "How'd you do that?" or "Do it again."

Dear Magician,
Those are certainly three very different reactions to an effect, but they are the three most common. Each requires a slightly different response.

When someone reacts by saying "I know how you did that," you must keep moving. Obviously you don't want to know or have them say out loud 'how' they think it was done. Not because they're going to be right or wrong, but because the focus will shift from your magic performance to a guessing game among your audience. So the best approach is to simply reply, "Good" or "Great, please don't tell anybody," and then immediately begin another effect, possibly with the person who's claims to know.

The "How'd you do that?" reaction is really an expression of surprise and should be greeted with a smile or at most a smile and the reply "Magic." Take such a question as a compliment and be modest about it, the same way you'd be if someone said, "That was great." In other words, you just thank them and let it go at that.

The "Do that again" command is really the most difficult to deal with. Most magicians know that it is usually not wise to repeat an effect. But the temptation can be very great to do just that. After all, the audience is in such awe of your magical powers that they want a command performance. How can you deny them that?!

If you're smart you'll learn that repeating an effect usually results in a disaster of one sort or another. Either they see through the effect to the method or else the effect just doesn't seem as amazing as it did the first time. Some magicians recommend doing a similar effect with a different method as a repeat. Mr. Magic is of the opinion that it is better to leave them wanting more and talking about how great you were.

As you spend more time performing and gain experience before an audience, you'll discover that all of these reactions can be controlled by your ability to use your personality to entertain an audience. In other words, these reactions are often the result of the trick rather than magician. The accomplished, seasoned performer has less of a problem with these kind of verbal challenges than those just starting out.