Some don't allow you to show your legs or bare arms. In Europe Americans stick out like sore thumbs because they have blue jean shorts and t-shirts with slogans on them. Sometimes this is not a good thing. You can put them in baggies if you want to keep your other items clean. You wear a good pair of walking shoes.
Sandals are great for evening.
You can always buy soap and larger bottles of shampoo when you get there. You do not need to bring a beach towel. It really prevents wrinkling and it keeps you organized. You could probably make your own. You can also purchase a packing bag that looks like a zip lock baggie with one way air vents at one end.