Cruising is not like other vacations. Most of the "work" is done for you. All you really need to do is decide on excursions and whether you want to try an upgraded dinner.
I'd say the only thing to "brace" yourself for is the crowds - a surprising number of people seem to have no self-awareness or believe they are **especially special**.
A few of my personal rules:
- don't use the elevator except during embarking/debarking. There aren't enough and less mobile people need them. I'm blessed.at 70+ to have good health and need to work off the calories anyway.
- no need to stand in line before dinner. Your seat is reserved. But don't be late either. You throw everyone's timing off.
-don't sit/stand on the steps (or allow children to). No running except on running deck.
-use inside voices inside the ship, especially residential floors.
-no saving pool chairs for hours if you are not in them. You move your feet - you lose your seat.
Mainly, just relax, be nice and enjoy.