I've had experience making posters.
EDIT: Read it wrong sorry >:( If you was to put things on it, I'd advise contact info, what you do, how much you charge ect... and do a magical design :o
I normally use the same line,
Me: "Can you keep a secret?"
Them: ".... Yes"
Me: "Good, so can I"
But if they seem truly interested in learning magic I will direct them where to start.
I advise just seeing if you could become one, just walk up to a restuarent manager / or ring them, and just ask if they would be interested in hiring a entertainer and with any luck they should give you an interview.
I agree, people over do it on practicing some times. Yeah sure practicing the method is great, but you also have to practice misdirection and many people forget that.
It's not a pick it up and do it in 5minutes job. A professional logo will take alot of practice and the right programs, Illustrator + Photoshop are good for logos.