Talk loud enough for every one to hear you and give enough force to your words to send them straight to the mark. Be careful of your language. Use judgment in what you say, and above all, speak correctly. Put expression into your voice and face -- avoid a monotone and a blank look. Put LIFE into your performance.

Create Interest in Your Spectators. Your problem is to arouse and to hold the interest of your audience. Be snappy in your work and your audience will be interested in watching you. If you give a slow, long-drawn out program your spectators will fall asleep -- and that spells tragedy. You must not, of course, go to the opposite extreme and work so fast that your audience cannot follow you.

The next factor in creating and holding interest is attention to what the public demand is — what they want you to give them. The wise magician, just like the wise merchant, studies the trend of the times and the kind of things people are clamoring for. He then capitalizes on this. He presents to the people the things they want and are willing to pay for and presents them in attractive packages, that is, in a pleasing form.

Study your program from the standpoint of the particular occasion and the particular audience. Try in your effects and in your "Patter" to come within the experiences of your spectators. Do not do things and say things that are absolutely foreign to their own lives and that they will not understand. Enter into their own lives and their own knowledge a little and they will give you their understanding and appreciation. You will then have their interest and the success of your performance is assured.
Harlan Tarbell was the mentor of many gnerations of magicians through his famous correspondance course The Original Tarbell Course In Magic