Don't tell your audience in advance what you are going to do next and once you have successfully performed an effect never repeat it, unless you are able to do so by an entirely different method. In many classics of magic, such as the Chinese Linking Rings (in which rings link and unlink again and again) or the Ambitious Card (in which a signed card repeatedly rises to the top of the deck), the effect seems to be repeated but the methods by which it is accomplished are constantly varied. If an audience member is truly baffled by an effect, the performer often hears, "Do it again." Unless you can do so by an entirely different method, don't give in to that request, no matter how passionately it is expressed.
