some hotels don’t provide with towels, so you better remember to take one with you. If your towel is heavy and takes a lot of space you could buy a lightweight towels made of microfiber.
sunglasses, contact lens, headphones, charger, jewelry box with you jewelry in it, make up bag, kindle or books, neck pillow, passport case.
credit card, personal ID and/or you driver’s license, cash and your health insurance card.
And surely don’t forget you number one essential for traveling: your passport.