Do a sleep aboard the night before. Double check everything before you leave. And if you have any questions during the briefing, ask.

We've found just taking the first day slow works well - we arrive, get settled getting gear, phone..etc and get on the boat when we can. We just eat at the restaurant right at the moorings keeping it simple and get a good night sleep. Next morning we head out as early as we can. You should be able to request an early briefing - we did ours at 7am which allowed us to get going early.

Other than that, have fun!