Keep yourself in good physical shape. That means eating well and exercising often. Wear the suit that makes you most comfortable. If you're at Black's Beach in San Diego, that might be your birthday suit. Be confident and vivacious.
Shyness is out.
Play on the beach and in the water. Lying out in the sun is boring. Flirt with everyone. You can develop a great psychological advantage over all those congenitally jealous creatures watching you on the beach. Force the hotties to use their imagination.