I grew up in a beach town. I've seen it all as far as beach attire goes. Some good. Most not so good. It made me want to be a better dressed beach goer yet still maintain the casual attitude that being near the surf inspires. I feel like one should be comfortable yet able to go into an establishment and order food like a civilized person when necessary.
To that end, a dress is my go to coverup of choice. It shouldn't be too short or too sheer, yet not too heavy since it must come out nearly perfect after being scrunched up in your bag and brought out for trips to the bar, restaurant, etc. Knee length sun dresses in soft cotton voiles and knits are perfect.
For this example, I chose a fabric combination dress from Zara. I love a straw bag that the sand easily flows out of, accompanied by what is apparently the best beach towel of all time, the Fouta, and, of course, a hat, sunglasses, and flip flops that can withstand the sand and sea. In my bag: plenty of water, sunscreen and healthy snacks. I try to pack light but invariably wind up carrying some of my kids' sand toys, if not one of the kids.