Beach attire is actually one category that I don't have many strong feelings about. It is very frustrating and difficult for me to find a bathing suit that I feel confident in so I am not one to create a lot of rules about what styles are appropriate. The most important thing (in my opinion) is to find a bathing suit that fits you and that you like, and if that isn't possible, to at least find something that you can stand being in for several hours.
There is only one point in this section on which Genevieve Antoine Dariaux and I are in agreement:
"The bright primary colours (red, blue, yellow, and white) are fresher-looking in the sunlight than more subtle shades such as mauve, moss green, or mustard yellow, which most often seem merely muddy." (pg. 14)
Now onto the points I take some issue with. She outlines a strict regiment for ensuring perfect looking feet during the summer season. From my experience, no one is paying that much attention to your feet. I like to wear a bright nail polish color on my toenails, but that is pretty much the extent of my effort. Also, she suggests that red nail polish is the only appropriate color for warm weather because it "will harmonize with all the different colours in your summer wardrobe" (pg. 15). I suggest that you buy a bottle of nail polish remover and change your nail polish color whenever it strikes your fancy or to match a specific outfit. You may prefer to wear one color for the entire season, but it is up to you how bold (or not) you want that color to be. If you end up disliking it after awhile, it is easy to change.
"[U]nless your figure is absolutely impeccable, unless you are under twenty-one years old and your skin is golden brown, it is preferable to wear a one-piece bathing suit." (pg. 14)
Dariaux, Genevieve Antoine. A Guide to Elegance. New York: William Morrow, 2003. Print.