I think these conquer my nerves fairly well.

A decent 12 year single malt whisky or two.

A laugh at someone elses expense. (terrible I know)

A quick jump up and down.

A hug.

A vivid imagination (so the audience are naked or soemething embarassing)

And just rehearse, the worst thing for nerves is making a mistake and then bottling completely. I used to play with an oversized hat pulled down over my eyes because I was nervous, (I play the flute n sing) and if I made a mistake I'd get upset and stop playing, it was awful, but now, I take a deep breathe smile and it usually goes well.

I still make awful mistakes sometimes, but it helps having a great band around you.