WOW... great question and even better answers! just my $0.02 but you didn't say WHERE you'll be diving and things are a bit different at each location - don't be afraid to ask the crew about anything.
1. to make your trip as comfy as possible try to find a boat that holds the LEAST number of divers. ie: pick the boat that takes 12 people instead of the boat that takes 30 divers.
2. listen to the DM about the upcoming dive. if he/she says 30 minutes bottom time, they're not kidding. nothing quite like the feeling of a boat full of divers glaring at you that have been sitting around in the sun while you're down there for 45 minutes!!
3. if you're diving in West Palm Beach things are a bit different as far as getting in the water is concerned. it's more like parachuting from an airplaine.... literally... EVERYBODY (or groups) goes in at bang, bang, bang. the captain will call out DIVE DIVE DIVE and boy oh boy, you better be ready. they're not doing it to be mean, drift diving is a bit different from your average run of the mill kick around the reef dive. you won't be making any friends if everybody's standing on the stern waiting for you to put your fins on!
4. do you dive buddy a favour and make sure they don't have any 'maskOysters' hanging around and on THAT note.....
NEVER use the mask bucket..... if you don't believe me just look at the thing at the end of the trip..... ewwwwww