3. Bring only the essentials
This goes for any beauty needs or toiletry essentials. Items like sunblock, moisturizer, eye cream, toothpaste, toothbrush, leave-in conditioner, etc — try to fit it all in one decent sized bag. Most hotels provide a blow dryer so you won't need to bring one. Remember to consider that any liquids you bring must be in a 3 oz. sized bottle. And don't forget those quart size zip lock bags to store them in!
4. Leave room for any extras
If you're the type that frequents island vacations most of the time, then you're probably one of those people that always brings your snorkeling gear. I always make sure to leave just enough room for them. Depending on the size of your fins it may or may not fit in your carry-on, so make sure to check the size first. Also leave room to pack your GoPro to document your snorkeling adventure ;)
5. Take advantage of your personal item
If ever you run out of space in your carry-on and still need a little more room, this is where your personal item comes in. I always use my Herschel Retreat Backpack because it's easy to bring around and it's pretty spacious. Also make sure to have any ID's, credit cards, passports, and important documents safely stored in your personal bag.