1. Yes, I know it's weird, but I REALLY REALLY want to you hear you tune your instrument. Do it as loud as you possibly can; I'll be happy.
2. If you make a small mistake that I wouldn't notice, don't make a face. IF, however, you make a Very Large Mistake that sounds ridiculously funny coming from you, feel free to smile or even laugh a little bit. It will make the connection even better; and, you'll seem like you're as human as the rest of us. Which is a good thing. But ONLY on SUPER HUGE mistakes.
3. General rule of thumb: it's always the guitar player's fault. It just is. So when you mess up, make sure to give the crazy person standing next to you a cold stare. Because it really was their fault...
4. If any of your first notes were out of tune for one reason or another, just stop, and make a very obvious show of re-tuning your violin. You could even add some helpful narrative, so the audience is SURE to understand precisely WHY you are re-tuning you instrument.
5. The sound guy is your best friend, or your arch enemy. Enough said.
6. Never. Wear. High. Heels. On. A. Boat. Because WHEN THE BOAT MOVES, the violinist gets sick. And THAT, my friends, is bad.