The usual
Move around the stage area
Project your voice
Engage your audience
Use your facial expressions
Laugh at your own jokes
Try not to piss your trousers
Most of all, enjoy yourself and, if you think you're any good, don't be put off by a few bad performances or lack of reaction from your audience. Even the best fall on their arse occasionally.

Personally, I'd run around torrent/Youtube looking at other acts - not just famous comedians but amateurs too. Make a list of what you like about their performances and think whether you can incorporate anything into your act/persona which will complement your performance.
( Noeli overtheshoulderboulderholderthingstraplatchboobs, Mon 4 May 2009, 7:31, Reply)