For fear of being "captain obvious", but I have not seen mention here, but have seen it all the time.

Duffel Bags and Backpacks, leave the rigid luggage at home. The charter company usually won't keep it for you.

We get cases of CHEAP 1 gallon waters, then we get 4 "NICE" 1litre bottles. Yes, we "decant" our water. Cheap water is ...cheap. The sun/sand/booze will dehydrate you... drink more water than you think you need.

Shorten the Dingy painter, really short.

The captain cannot hear what you are saying at the front of the boat, shouting just adds drama....and comedic relief for us watching...yes, we watch