Hands down one of the trickiest (kinda) parts of the wedding invitation elements. Deciding on the attire wordage ranks right up there with getting your eyebrows waxed. It's no fun, but ya kinda gotta do it.Here are some articles and tips I found helpful from Wedding Channel, the knot, Destination I Do and Martha Stewart Weddings.
Now here's my 2 cents for destination weddings:
Island casual: Light weight and casual wear. Most guests will take this as nice shorts and short sleeved button up shirts or polos for the men and simple sundresses for the ladies.
Island/Tropical elegant: Again lightweight, and short sleeved, but adding a minimum of slacks and a full length sundress. Certainly less than sequins and ties though.
Resort elegant: Nearly the same as cocktail, only with lightweight fabrics being appropriate. No shorts, no sundresses. Yes to ties & slacks and cocktail dresses without sequins.
I do find it nice to state on guest guides when hats and/or wraps would be a benefit or appropriate.
{Quick Tip} J Crew currently has the best hands down grooms/groomsmen destination wedding suits available. Just sayin.