The best way to do this is to present the image of a solid, professional, eager, and intelligent comedian, both on-stage, but just as importantly, off-stage. Therefore, this article will discuss some rules for behaving as an emcee, not for the benefit of the audience, clubs, or the other comedians, but to advance your own career. Having opened for dozens of headliners, and made a bunch of mistakes, I am passing along these words of wisdom.
1. Be Professional.
No matter whether you're opening for Chris Rock or some yutz you've never heard of, be professional. Remember that you are both comedians, both professionals, and act as such. If you're a big fan, keep it to yourself, or at least keep it short. If you like his (or her) set, compliment them - quickly. Say, "Nice set in there." Don't blabber on and on. Headliners hear that all the time from fans -- they don't need to hear it from you.
2. Do the introduction as instructed.
In my first few attempts at emceeing, I was scolded on a couple of occasions by different comedians for adding to or changing their introduction. Whatever they tell you to say, write it down, and say it word for word. Even if you think you're helping, or being complimentary, some headliners don't want to hear that they're "the funniest headliner we've ever had." As one said to me, only half-jokingly, "I don't want the bar raised that high."