Don't drink! At least, not before the show ;)
Just trust that you guys know your stuff, and ignore the audience except when they cheer, and play your little guts out. More importantly, you must believe that you are awesome enough to fake your way through if you do mess up, but you're not going to mess up because you are That Awesome.

good luck!

If you normally wears glasses, take them off before the set.

You don't need it mulp but good luck to you.

Here's one coping strategy, mulp:

It's quite likely you won't be the only just-about-freaked-out-musician on that stage. But it's possible you'll be the only one with the presence of mind to tell each of your bandmates what hella job they've just done, in near real time. Yep, you're the drummer, and if you want to be, you're their biggest fan!

You'd be surprised what a kick-ass attitude, behind the kick pedal, can mean to a band, its first time out.

I know what you mean, I played my first show a month or two ago, and I was really scared. You're going to fuck up, but unless you say "OH SHIT I FUCKED UP", no one will notice. Drink a couple of beers to relax you (especially if you get drink tickets), but most of all just remember that you're just there to have fun and if you fuck up you, fuck up and if the crowd loves/hates you, they love/hate you.

Bring joy to many people with your music, like my boyhood hero Country Dick Montana, a blessed drummer. (You'll have to click the other links to see him behind the kit.)

No matter what happens, keep that beat going on the kick drum. If the band trainwrecks (and they will), it is up to you to reestablish the groove.

The easiest way to do that is to vamp measures of simple "ONE two three four" on the kick, and if the guitarist and the bassist are just staring at each other with that "Now WTF" look (and they will), count it out vocally and shout it as loud as necessary.

You want to reconnect with the bass first, and if your guitarist is smart, he'll fade in with a sustained chord.

Remember the old bluesman's motto: If you make a mistake, do it again. People will think you meant to do it and that you're a freakin' genius.

Have fun, and look like you're having fun. Nobody cares if you fuck something up, but if you get obviously upset about it, that's not so cool.

Some of these are just general band advice...

After the show, even if you sucked, don't apologize to anyone not in the band. There's a good chance you might be talking to someone who enjoyed your set and saying "I'm sorry we sucked," will put them in an awkward spot.

I second don't drink until you're done playing.

I'd also like to add, don't dwaddle setting up your equipment and bring only what you need (don't bring that rack if unless you're in a motley crue tribute band). Also, don't borrow equipment. If you're not playing first, set up your drums off to the side during the band before yours set.

Never stop a song because of a mistake.

Practice as much as possible between now and then.

Don't bad mouth other bands anywhere ever (I learned this the hard way).

Once you're into your first song you'll probably stop being nervous.

Don't let the guitarists jump into the drum set.

Don't sleep with anyone in the band, anyone in the band's significant others, and anyone in the band's ex-significant others- even if they tell you it's ok.

Don't get T-shirts made until people are practically demanding them.

Think of the groupies.

Essexjean, in my personal experience, unless you're in high school, or in a highly successful band, there aren't many groupies (except those clearly underage), but i guess that depends on what style of music you play

(I've been in a metal band, a ska band, a punk band, a handful of indie rock bands, and a somewhat successful band that didn't play any of the previously mentioned).

second don't drink until you're done playing

Third that. It's a terrible trap, because you think it will relax your nerves. In most cases, it doesn't have a good effect. I was in one band that had a terrible habit of a couple pre-show pints. We always thought we sounded great, but occasionally we'd get a recording back of the performance...and recordings don't lie.

But do bring a water bottle, and keep it nearby for a quick swig between songs.

Also, make sure you've got a bandanna or something on you or near you in case you start sweating too much. Some sweating is cool for a drummer, but too much could interfere with your concentration by getting into your eyes or itching in your hair. It's amazing how much performers can perspire - some combination of being physically active through playing, usually having some stage lighting on you, sitting amongst big pieces of equipment which emits heat, and having a roomful of people looking at you always seems to turn the calmest of musicians into a sweat-sponge. Dress accordingly, too - dress for a room about 20 degrees warmer than it'll actually be.

You have my envy!