as the house magician, how to you walkaround the restaurant?
There are different options. Personally, I keep a watch on the waiters. This way, I get an idea of what tables would be good to perform at (as in time issues, so I can make sure I have enough time to perform before the food arrives). I also listen to the waiters as they will tell me if there are tables that it would help if I performed at (for instance, if their food will take longer than expected). I also look at the customers. If they look bored, I'll go and talk to them, and perform a little magic. If it's a family, and it looks like they need a little help with the kids, I will go perform for the kids there. You really just have to keep your eyes open.
do you need to go from table to table?
I personally go from table to table. I've heard that some restaurant magicians just have a table set up somewhere, and perform there, but I personally don't like that idea. I'd personally would rather just walk around, from table to table.
do you only perform for them before their food arrive?
That and maybe after they are done eating. But only after if it's a slower night. If it's a busy night, then only before they eat, this way I don't keep anyone their longer than necessary. Never perform while they eat though.
what do you do when everybody is having their food and you have free time?
Being a restaurant magician isn't just about the magic. You're basically an ambassador to the restaurant. Keeping that in mind, I will go around to certain tables if I think they look like they need something. I will ask if they are having a good time, and if there is anything that they need. Now, if they need something, I don't get it for them, but I inform their waiter. Many times though, I will just go around and make sure that everyone is having a good time, and make sure everything is right.