This is finnally somethign I can comment on.
For years I went through the same thing. (I am in High School now)
The magic secret I found out was to NOT tell them to **** off or tell them to go away.
What I do, is if I feel like performing, or if they won't leave me alone, I do like an impromptu show of say, 20-30 minutes of magic.
I won't say that I never run out of material; everyone does. When that happens, I reccomend turning it from magic to comedy. I end up just joking around with everyone, practicing different comedy sets.
It is kinda hard to explain; just roll with the flow. Always leave them wanting more. Another thing I do is I will pull out my bussiness card and just tenkai palm it over and over until someone yells, "WOAH!". I hand them the card and they seem to be more amazed by it then my magic.
Don't tell them anything that isn't profffesional; treat them as if they were paying you to do a show. But don't be a performing monkey. You will find the balance sooner or later. Right now, in total, I only perform about 45 minutes a day at school; comedy and magic.
If you must have one more thing, then make up something on the spot. Try out some new moves. Pick up some crayons off the floor and do something. Do a book test. Whatever you can.
(Performing a lot at school, you can generally get the teachers involved which is a great way to get on thier good side.)
Hope that helps!