Do whatever it takes to loosen yourself up before you play…It will make the world of difference…tug one out have a drink or 2, listen to that one song that really gets your blood going.
I still get jitters here and there playing, and for me…this will sound really weird, but listening to ATB no rain over paradise while eating some pizza pockets before i get to the club is my usual routine…then i usually slam back 2 shots of jager and grab a couple of beers is my routine. Even then i still get nervous if its in a new venue.
As well its good form to show up early to your show so you can get comfortable and not have to rush in set up and play right away.