Have lived there and cruised there numerous times - never get tired of the perfect humidity free weather, the beautiful beaches, the fabulous islanders.
Tip 1 - The sun really is different there and when people say "I never burn", they probably haven't been to the islands.
Tip 2 - Water shoes are a MUST on the beaches due to the many "critters" that wash up. Step on a sea urchin or jelly fish and you will see why.
Tip 3 - Many islanders survive selling their wares (not talking about big chains with US owners). Respect their craft, pay their price and hear their stories. They are an interesting group of people and chalk full of info. This is not Mexico.