Write down the material and get to know it well. Ifthe jokeretains its funny quotient even after several read-throughs, then it's safe to assume it's solid material and will be effective when it comes time to actually deliver it to a live audience. Moreover, practicing constantly may help to relieve or keep in check anyfears.
Know the audience. It's critical to do this to avoid delivering jokes that the audience mightfeel are entirely inappropriate andinsensitive. For example, jokes about harmingdogs might not get a laugh if they're given to an audience of staffers from theAmerican Society for the Prevention of Cruelty to Animals, no matter how much they might be able to take a joke.
Be mindful that some people in the front row can be chatterboxes and possibly loud to boot. Be prepared for how to handle that situation. For example, stand in front or near the talkers and become more quiet so that their voices and volume become more noticeable. If this doesn't work, then perhaps have a joke ready specifically to call out such offenders.
Embrace failure. Know that newjokes must be tried out and that some will work and some won't work, but taking the risks is necessary. It really is necessary to be willing to fail as often as possible to succeed as a stand-up comic.