After reading all this garbage from people that have never even see a working restaurant entertainer I have to say something. You MUST have a costume that you wear for your shows. Whatever costume that your character feels comfortable in. Professor Paddy, my performing character, is from the old medicine show days. So I wear grey slacks, with suspenders, white long sleeved shirt, a very colourful vest with playing cards pictured on it, a string tie and a bowler hat. My hat and vest makes me stand out in any crowd and I look like and talk like an entertainer, not like the staff and certainly not like the customers.
If you have to ask what to wear that means you don't have a performing character and if you don't have a performing character you are not ready to perform. What is a performing character? Very simple, I as Peter don't perform magic. I practice but not perform. Once I get into character, Paddy now firmly believes in his magic. When he palms a coin, to him it really disappears. It's gone until he brings it back. If you can't do an effect a not believe in the magic, you can't convince your audience that they have just seen the impossible happen before their eyes.
Unfortunately, this is one of those nuggets of magical knowledge that it usually takes an F from the school of hard knocks to teach. The proper mindset for the performance is key to performing convincingly. As Paddy said, the coin must be gone in your mind as well as in the spectator's. If you don't ackowledge the coin's disappearance, you'll palm it too hard, you'll glance at it, you'll hint at its presence. . .
I don't have a secondary personality for being a performer - it's just a more excited and amped up version of myself. However, there is a confidence that isn't there when I'm not performing. I can get away with poking fun at people and making assorted jokes that would be deemed vastly inappropriate if I made them elsewhere.
P.S. Oh, and wear a jacket.