Trip activities
You need to account for space your surfboard, snorkeling kit, or your rock-climbing gear is going to take and check the guidance on how you can fly/travel with it.
You might want to look up options of how and where to rent equipment at your destination or travel by car, so you have more room. Another option is to book with a company that offers package trip activities and equipment.
Your activities will also influence how many outfits you need, if you’re spending all your trip in a diving suit then you won’t need as many outfits compared to a trip exploring museums and going to fancy dinners.