1. Oversize floppy hat. Nothing exudes mystery at the beach like an oversize floppy hat. Plus, it keeps your skin looking good. Win-win. San Tropez hat, $54 at Fred Flare.
2. Winged tip eyeliner
2. Get that signature winged tip eyeliner look all of the famous sexpots wore, but BETTER: this version is not only waterproof, but it comes with a felt tip so it doesn't take all morning to apply. Girl's got things to do! Buxom Waterproof Pen & Ink Long Last eyeliner, $20 at Sephora.
3. Ruched retro one piece
3. Ruched retro one piece. Norma Kamali is an old school beauty herself: no wonder she knows all about how to get just the right amount of ruching to make your bod look slammin' in a one piece swimsuit. Norma Kamali mailott, $350 at Net-A-Porter.
4. Retro Mailott
4. Retro Mailott. Oh, hey, another gorgeous one-piece. Because pin-ups don't go to the gym--they're totally secure with their voluptuous bodies. Show it off in this black and white Cannes mailott, $138 at Anthropologie.
5. Cat eye sunglasses
5. Cat eye sunglasses. You kinda can't even try to be a retro sexpot without a pair of these retro staples. Luckily, they're on-trend so you won't look super costumey. Elizabeth and James cat eye sunglasses, $155 at Zappos.
6. High waist, printed bikini
6. High waist, printed bikini. Gonna go full-on bikini? Do it the retro way, with high waist swimsuit trunks, and stop with all of those crunches. Summer is here--time to celebrate, not start a fad diet. (Am I right?! Who's with me?) Retro poppy bikini, $78 at Anthropologie.
8. Halter bikini
8. Halter bikini. The gorgeous technicolor cobalt blue color of this classic halter bikini is what glamour is all about. Charlie by Matthew Zink swimsuit, $105 from $210 at Net-A-Porter.
9. Platform shoes
9. Platform shoes. Flip flops do nothing for your legs: show off your cherry red pedicure and your hot gams at the same time in these aptly-named platforms. Pin-Up platforms, $90 at Anthropologie.
10. Gingham top
10. Gingham top. This is always classic for summer--wear this effortlessly sexy top with your high waist bikini bottoms (and the platforms!) and you're in business. J.Crew gingham shirt, $175 at J.Crew.
11. Polka dot retro bikini
11. Polka dot retro bikini. Is there anything sexier than this extreme polka dot bikini? Norma Kamali from $195 at Bergdorf Goodman.
12. Red lipstick
12. Red lipstick. A Marilyn without her red lipstick was unheard of. Waterproof red lippy to the rescue. Aqua lip pencil, at Makeup Forever.
13. Corset romper
13. Romper. With a built-in corset top, this is practically calling Marilyn's name. Just add some lipstick! Twenty8Twelve romper, $360 at Shopbop.
15. Printed short-shorts
15. Printed short shorts. What's a beach blanket bingo party without a pair of super tiny printed shorts? Tory Burch printed shorts, $78 from $195 at Tory Burch.
14. Matte Sunblock
14. Matte Sunblock. Those old school glamour girls shied away from the sun: a perfect excuse to lather on that SPF. Get rid of the greasy look and feel with a picture-perfect matte sunscreen like this Murad oil free matte sunscreen, $31 at Sephora.
16. SPF shampoo.
16. SPF shampoo. After studying hundreds of photos of Bettie Page and others, one thing I've noticed: pin-up girls rarely get their hair wet. Whether you're a swimmer or not, use an SPF shampoo so your scalp doesn't get burnt, 'cause that's not hot, either. Warren Tricomi Pure Strength shampoo with SPF 15, $20 at Amazon.
17. Sexy hair--and Bobby pins
17. Bobby pins are your friend, too. Use them to give yourself a Brigitte Bardot messy bun or just part your hair to the side and let the beach wind do the trick. These are the cutest we've found. Flower pins, $4.50 at Charlotte Russe.
18. Striped tee
18. Striped tee. There's a reason this tee is named after Brigitte Bardot: it's effortlessly chic and perfect with a bikini. Bardot tee, $92 at Piperlime.
19. Polka dot pants
19. Polka dot pants. Want to exude even more mystery? Try these polka dot pants on your walk to the beach or poolside. $145 at Revolve Clothing.
20. Printed shorts
20. Printed shorts. OR, Show off those legs, girl! Wear your retro halter bikini top with these adorable Kenny "pin-up" shorts, $100 from $143 at Shopbop.