Here is my packing advice:
1) Select outfits for dinner where you can mix and match. For example, I bring about 2 dress slacks and 3 different tops that can be mixed/match. I will do the same with DH (1 dress slacks and 3/4 tops). Same for DS.
2) Because we tend to buy some T-shirts, I will normally pack 2 for me and DH.
3) Since we will be wearing our swim suits 2 of the 4 days (Dolphin Encounter excursion and CC), that helps out.
4) I don't pack socks, sandles are fine for us.
5) I will not do laundry while on vacation - that is just my rule.
They do have hair driers on the ship but I liked my better. I plan on using their shampoo and conditioner this time (saves space). You don't need to bring beach towels, the ship provides plenty.
My last but final suggest/rule/advice, HAVE FUN!!!