Personally i prefer not to wear anything. (!) no just kidding, of course the killing hot summer makes us think why not right? but still..
Anyways what i prefer to wear in summer:
Going to the beach:
tank tops or cheerful tshirts
(xl tshirts if I'm going surfing)
For the ones who like to spend time on their looks (to look fancy in other words :) ):
Add some nice simple earings or/and bracelets and necklesses
a catchy bag
high heeled flip flops
will continue with different locations..