The best way to avoid nerves is to be organised. Pack the night before, and allow plenty of time for you to get to the venue.
Far better to be safe than sorry: no matter how experienced a shot you are, nor how exciting the drive, there is never any excuse for not being safe.
Ask before you take a dog. And if you do take one, be certain you can rely on their steadiness at the peg.
Say thank you, to host, keeper, beaters and pickers-up. They may all love what they do as much as you, but courtesy goes a long way.