If you have never been on a cruise before or never been on a Royal Caribbean cruise I suggest skipping the dining packages. There is a ton of food available and the specialty dining menu’s stay the same but the Windjammer will swap in food that is local to your next stop most times, for instance going to Jamaica you will get jerk pork and/or chicken with rice and peas among other things you would often find in Jamaica. If a country has a local style of cooking odds are the dinner meal the night before will reflect that. You will still have some standard things a lot of times so anyone can find something they will like. By booking the restaurants you are limiting yourself a bit and you already paid for your food. Been on a ship multiple times on the same route or celebrating something special I say go for it but otherwise stick with what is already there.

Late night on most ships you can still stop by the Café Promenade or Sorento’s Pizza (smaller ships may not have one) and grab something to eat or take back to your room to eat.
Main Dining Room (MDR) can be a pain. First few times I booked My Time Dining (MTD) and honestly wasn’t worried about going to the MDR but my girlfriend wanted to go one night but when we went to try and book a time nothing was available. The only way to get on the list and not have to wait in line was to speak to someone at the MDR ahead of time to get a table so honestly I suggest skipping MTD and pick either the early or late dinner so you can catch shows. It doesn’t force you to eat there but if early dining starts at 5:30 and you are not there by around 5:45 they assume you are not coming and will start seating MTD people who are waiting in line. And remember the MDR is open for breakfast and lunch and will have less people as most will head to the Windjammer.
The Ultimate Beverage Package or Soda Package or Beverage Packages are fine if you drink a lot of whatever you are after but most require multiple drinks per day to break even over purchasing things outright. And remember that you CAN take on a couple bottles of wine and a 12 pack of soda can’s or bottle’s if you really need a fix. I was on Liberty of the Seas for 14 nights and two bottle’s of wine was all we took on then picked up a drink here and there if we wanted something.
I carry a drink container and fill it up when we eat, but it can also hold a full bottle of wine and that is what I used when on the B2B headed through the port (it was amazing). Also remember that there is free coffee, hot water and tea bags or hot chocolate packages, Nestle Vitality drinks, water, or in the mornings juices, or milk available for free as well. The Nestle Vitality drinks are often changed out throughout the cruise and remember that you may need to add some sugar or sweetener for it to taste correct for the drinks available. You can easily carry along some of the "water enhancers" as well if you just want something you enjoy but don't want to spend a ton extra.
You can carry something that has an HDMI output along and hook it up to the TV in the rooms. I personally carry a Raspberry PI 4 with RetroPie and a bunch of ROM’s for when I don’t want to just hang around the pool. I also load on a few movies to watch whenever. The only other thing you need is some sort of wired controller. Plus it’s kinda nice to play some old retro NES or SNES games.

If you have a tablet I highly suggest loading some movies or shows onto it to take along as well. You may have some times where there isn’t much happening and it does help to pass the time. I actually have a few movies and TV shows as well as some Ebooks I carry along on my tablet.

A multiport charger is almost a must if you don’t want to play the device charging shuffle. Then you can add your regular cables and charge everything up in one shot. You can not take along extension cords or most power bars because they are considered a fire hazard and you will likely only find a couple outlets in most staterooms. I carry a phone and tablet along with a couple Bluetooth speakers and a pair of chargers for my GoPro batteries. Add all that to my girlfriends tablet and phone and let’s just say that if you had a single device charger nothing would be charged up fully unless you are in a suite with multiple outlets and multiple chargers.

Everyone seems to have similar suitcases, black is especially common. I have some luggage tags that work great with the printed luggage tags that Royal Caribbean provides. It makes your bag look a little different and can also be used when getting off the ship. I just pull the paper one out and wrap the one for leaving around it then slip it back into the pouch. They also can come with some lanyards which work nicely for carrying your SeaPass and a couple bucks, haven't had an issue yet since having them or the tags. And getting a handle wrap will help identify your stuff even better, you could draw a picture on some plain ones so they get to get in on getting things ready as well. In October I did have one woman grab ahold of my girlfriends suitcase and she would NOT let go, her husband had already grabbed hers and I tried to get her attention multiple times and she ignored me until I took ahold of her arm to prevent her from walking off.

If you are planning to take a cell phone with you it may be worth grabbing some pouches to keep them protected. I have personally seen them pulled out of the water after over a year and had the phone still work. In fact I took one to around 30 feet after finding it in the water. A dry bag is not a bad idea either if you will be around water and would like a dry towel. I SCUBA dive and carry a dry bag for my towel, some dry clothes, my tablet, and some spare batteries for my camera. Tablet still works like the day I got it and while on the ship I toss my phone inside and clip it to something so it doesn't walk away. I would look at as large of a dry bag I could get though. I have a 10L one and it's actually too small for excursions and I will probably grab something closer to 20L next time.

Towels are available on the ship for use at the pool and for excursions, just remember to bring them back and make sure they scan your SeaPass when dropping them off so you are not charged for a towel. Another hint is grab some towels and roll your wet clothes up in them and then twist the towel to get as much water out of your clothes as you can but especially on the last day. You can hang them in your room and they will be dry the next morning if you did it right.

While on the ship there is a cell tower that is turned on a certain distance from shore. Some service providers have a contract and will automatically connect, this is not generally covered with unlimited roaming of any kind so you may want to put your device in airplane mode while on the ship. If you do splurge for internet you can simply turn WiFi on after turning on airplane mode. You can make calls over the ships internet connection though they may not work exactly right. If you have an Android phone and calling doesn't work right download the Google phone dialer app and set it as default while on the ship and it should work fine if you have WiFi calling available. Can't help with the chewed on fruit devices though, sorry. I have Android devices and have had decent luck with doing internet sharing as well. I connect to the WiFi with 2.4Ghz and then rebroadcast to my tablet with the 5Ghz band. My S21 5G has no issues but I can not say every device will work so your mileage may vary and it will EAT your battery so keep it to a minimum unless you have a big battery, have a portable battery, or are plugged in to a charger.

When packing I suggest having everything packed and in the car or as close to the car as possible the night before. It forces you to remember the little things sooner than if you leave your bag in your room till the last minute. It’s a lot better to be walking around searching for a pair of shoes or something at 6 in the afternoon the night before leaving than the morning you are heading out. And DON’T forget the vaccination card, for COVID tests and boarding pass, get a copy on your device or something printed off in case internet is spotty in the terminal.
If you are flying get in at least the day before… with all the canceled flights you may want to spend two days in town instead so if your flight is canceled you can hopefully get rebooked. Driving is another option and my preferred way to get to the terminals. I still get in the day before and have a room booked and prefer to get in a couple days before if I can so I can explore a little. And remember that Amtrak can get you to a lot of the ports as well and will have a lot less cancellations on average but again plan to get in ahead of time. Unless you only live a couple hours from a port you probably want to spend the night within about 15 miles of the port so you have more options of getting there on time.

And if you are not finding an excursion you like through Royal Caribbean you can take a look at some other places to find them. Shore Excursion Group is one that I have used in the past and they offer similar guarantee’s as Royal Caribbean for getting back to the ship.