Some general packing items I recommend:
1) A small/collapsible umbrella
2) Backpack for excursions
3) Liquids, can buy water/soda/wine at the embarkation ports supermarket and drop them off with the porters
4) Air Freshener
5) Backups: Bring two pairs of sunglasses, backup phone charging cable and if you're sensitive to the sun, I always bring two hats, one that I try to keep dry and the other I may use while in the hot tub, pool or on an excursion where I'd expect to sweat a lot