1. Don't bring too much gear. half dozen rods is ok but showing up with everyone you own will be cumbersome for the boat and you.
2. Be ready to move. Depending on the angler, you will be of help to both of you if you are ready to go when they want to move. Since it is a bass boat you will want to keep things picked up so that you are not taking too much time to button down for the ride.
3. Discuss use of the net, casting preferences (depending on fishing structure), and any special gear the boater may want to fill you in on (maybe use of the trolling motor or livewells?).
4. Be safe. My bass boat would only go about 67 but I knew friends that could get into the high 80's with no trouble in a loaded boat with a 250HP. That leaves no room for mistakes at that speed on something w/o brakes.
5. Have fun and catch some fish.
As far as fishing, you may want to be ready for any type of bass fishing the boater may do. Have a spinnerbait or crankbait rod rigged up for faster fishing or if the wind picks up, something that will fish the surface such as a topwater bait, something for deep water fishing (10-30 ft) such as a carolina rig or weighted plastic or jig, and if you have enough rods something that will throw a weightless soft plastic bait such as a senko or a worm.
It can be a lot of fun and is super addicting after you have started T fishing for bass. I loved it a lot and may someday do it again.