You do not want your clothing to promote sweating and collect it like a sponge. What you do want are fibers that are going to wick away moisture and let it evaporate. That means no cotton. Wool wicks moisture, but is horrid in the sun, so skip that as well. Look in the athletics section for tops that are specifically made to wick away moisture. Holiday shirts are also great for keeping you cool. Pull off button up holiday shirts with style by wearing them slightly loose and with a neutral pant.
The last thing you want is to have a bathing suit that is falling off your body. You also do not want to appear shapeless, if you decide to wear a top to the beach. However, you should not wear skintight clothes, either. They keep your skin from breathing and can stick when they are wet. Go for something that is just loose enough that you can move comfortably and that does not cup you too much in an area you would rather keep private.
When picking a bathing suit, go for a short that is about two inches above the knee. The higher above that it goes, the creepier you will look, unless you have quads like Daniel Craig. Keep it casual. Pick a solid neutral tone so you look classy and clean.
Shoes and hats
When you are headed on a beach vacation, there are three shoes you will need, though you can dispose of one in a pinch. You need canvas or boat shoes for casual day outings, walking shoes for hiking and sandals for the beach. Sandals should be sturdy. If you like flip-flops, bring extras.
The key words to remember when packing for your beach destination are cool and casual. You want to look and feel comfortable at all times. That does not mean you should wear linen pants to a formal dinner, but that you should be wary of the temperature so you do not sweat over cocktails.