For daytime ashore, take clothes you can layer, such as cotton sweater/sweat shirt. It may be warm or cool. I find a waterproof poncho with hood and lots of pockets indispensible. Of course, very comfortable walking shoes, binoculars, camera (extra film).
For formal nights, I take separates I can layer ... dress things up with scarves and jewelry. One black silk suit, with pants and long skirt, mixed with assored tops and jewelry could take me around the world!
Have a fantastic cruise!