caruso:
That's a very vague question. However, I will try to answer it.
It depends on the group you are performing to. If they keep wanting more and look interested in seeing more, perform one more. The important thing is to keep an eye out for signs of disinterest, distraction or coughing. These simple signs show your audience is getting tired and losing focus. Quickly wrap-up with one really good trick, and take your leave with dignity. One mistake I made (and sometimes still make) is that you perform for too long, thinking that the next trick will get the "reactions". Instead, you not only get boring, but long-winded as well. So remember - do until a certain level, end it with something nice, and leave.
Routine? You may wish to have a set of effects chosen from your "arsenal" ready for performance anytime, and they should pop into your mind immediately and quickly when you start performing. On the other hand, you may wish to use the "randomizing" and "jazzing approach" - you just do anything that comes to your mind. It could be just a simple thing like multiple french drops and you just jazz it into a really impromptu routine. (I believe Huron uses this approach and is very successful in doing so. I've tried it before myself, and I used a coin and a spongeball and did a random, totally impromptu routine with them.)
Hope what I said helps.
- harapan. magic!