Here is the link for the cruise tip calculator, just in case you haven't come across it in the other threads
http://cruisetip.tpkeller.com/
Are you travelling with kids? We took pillowcases to guest services on our first night. On the last night they were delivered to our room with all the characters autographs on them.
We did take a case of water onboard, as we needed it for the baby formula. I had read that it could not go in checked baggage, but we were able to check it in. It was handy to have the bottles to refill. We had a fridge full of water.
I will also pass on a tip our server gave us for
Castaway Cay, but it is for the family/kids beach. Our server told us to make sure we were off the boat early. Once we got off the tram, we were to keep walking until we passed the Bar, then go down the path to the beach. He said this was the best spot on the beach as it was near the toilets, and the food, plus the lounges were underneath palm trees so they got shade most of the day. We had the best spot. We did get to witness some sun lounge rage though, with people taking other peoples lounges when they were in the water or had gone to get lunch. We always left personal belongings like caps on our lounges and they did not get touched. It seemed to be the ones with only towels on them that got taken.
Your cruise itinerary looks awesome. No wonder you are excited!