Don't try to do everything...most people can't be in 2 places at once
If this is to be a relaxing and rejuvenating cruise, bring whatever helps you do that (I restock my kindle prior to every cruise).
If this is a more active, attend many activities kind of trip (and many people going many directions) then highlighters for the navigators (when we would do this for our family we'd assign a color for each person, leave it in the cabin and at a quick glance, know where everyone is...or thereabouts). There's an app with the navigator but the old school way allows for an immediate visual of the entire party (or maybe I just don't like technology!).
In the old days, we'd use a dry erase board and put it on the interior of the door to leave messages for each other. That changed to post it notes...now I believe most people use the wave phone or the app. Disclaimer- I've never used the app but DH says he could text other members of our party using it.
Some folks like to bring a nightlight for the room, some will bring a clothespin to secure the curtains (to keep out the sun/provide privacy in the room divider), some a non plug in air freshener for the restroom. I've never done any of these but they make sense.
I DO bring a used hotel key card or an old store rewards card for the light switch and leave it in for the duration of the cruise-hard enough to remember where my key to the world card is without having it provide power. You'll see lanyards for sale somewhere (all prior cruisers have them given gratis)-consider whether you're a lanyard user or not and if you have one at home that can hold a card bring it so you don't have to buy one.
There is a drug store not too too far from the port so if you forget something last minute it has lots of "oops I forgot" items. Shampoo, conditioner and soap provided so unless you have to use a specific kind then don't worry about packing that stuff.
The assembly drill the day of departure is NOT OPTIONAL (sorry, pet peeve). If your muster station is outside, it will be hot in the summer, possibly rainy, possibly cold in the winter. Prepare for those possibilities. The horns are loud but they give you a warning to cover your ears (or the kids') so it's not that surprising.
I usually end up doing laundry on cruises that are a week long--there are self laundry stations on some decks but not all and they have more machines in some of the rooms than others (odd). You pay with your key to the world card so no need to haul around quarters. There are very good instructions on the wall but if there is a problem there is a phone you can use to call someone who will come help. If you do laundry, check your washer/dryer frequently (or set a timer). People get a little testy in the laundry room for some reason and I usually end up getting up early, doing laundry and just reading in the room to avoid and toes getting stepped on. This is also where the iron and ironing board is and this can get busy on certain nights.
Pack and wear what you want. Lots of discussions about too formal, not formal enough. Live and let live sartorially (except in Palo/Remy, they do have dress codes). I get cold in the MDRs so I always take a sweater but I'm a thin blooded Southerner. So you might not.
But mostly...have fun and enjoy your vacation!
- well no extra charge at least since you've already paid for it) if you don't like what you ordered first.
