The 12 Sexiest Summer Hairstyles

When going for a thick braid like Scarlett Johansson's, keep the direction of the plait in mind, and be sure to use a mousse beforehand to give the style extra hold. "The braid is shaped on the outside -- it's important to know where to start so you'll know where to finish," said her hairstylist Alain Pichon. "On Scarlett, I started behind her right ear and worked down across the nape of her neck so the front would be thicker, and so I could seamlessly tuck the rest of the length into her style."

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Short crops like Ginnifer Goodwin's are ideal for staying cool in the summer heat. After blow-drying, run a styling wax or thick molding mud through random pieces of hair to bring out the texture and create light separation, particularly in the bangs, to keep the style from appearing too blunt.

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The trick to a perfect bun like Lauren Conrad's? A foam hair insert like the one from ASOS ($9; asos.com). They take the guesswork out of forming an ample updo -- all you have to do is roll them into place. Conrad's hairstylist Kristin Ess split her hair into three sections, then rolled a straight-line hair foundation into the back to create her bun. "Drape the two side sections over your bun, and if you need to, wrap them around a curling iron first so they blend seamlessly," Ess said. And don't skimp on the bobby pins; since the foundation adds weight to the style, use more hair pins for extra support.

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For a style that requires no heat tools at all, wear your hair in its natural texture like Solange Knowles. Incorporate a hydrating shampoo and deep conditioner like the Carol's Daughter Black Vanilla Hair Smoothie ($20; carolsdaughter.com) into your routine to keep the summer elements from drying out your strands, and avoid putting your hair into styles that pull on it to keep breakage to a minimum. "Before I shampoo, I comb out my hair with a wide-tooth comb," Knowles told InStyle. "The wider the teeth, the less strain and breakage you're going to have."

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Loose, tousled waves like Emmanuelle Chriqui's are a summer essential. Humidity actually works with the style to create a carefree feel -- meaning hairspray is optional. Allow your hair to air-dry to bring out your natural waves, then loosely wrap sections around a medium-barrel curling iron. Rake your fingers through the ringlets after they have cooled to rough up the texture.

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Charlize Theron gave the side pony a twist by rolling it up across the back, and keeping it low. "This is a very minimalist look that is still appropriate for events," said her hairstylist Enzo Angileri. "I wanted to eject some glamour into the look, but wanted to keep it simple as well." Angileri started on one side of the star's head, twisting her strands upward and working from the left to the right. After a ponytail was created, he secured the style with bobby pins and finished with a spritz of Moroccanoil Glimmer Shine ($26;moroccanoil.com for locations). "I didn't use hairspray because I wanted the look to be completely natural and loose," he added.

Extra volume is an easy way to add a Brigitte Bardot-esque flair to the traditional ponytail. For a style like Eva Longoria's, start with clean, blown-out hair, and tease your top layer at the crown using a fine-tooth comb. Sweep a layer of un-teased hair over to cover the backcombing, then fasten into a high ponytail.

We love the high-fashion feel created by Gwyneth Paltrow's ultra-smooth bun, and how her perfect center part makes the style graphic. A little shine serum goes a long way when recreating this look, so smooth a dime-sized drop through before securing the style. While wispy pulled-out layers work with other summer styles, Paltrow's look is all about the sleek texture, so keep a flyaway tamer on hand to maintain the streamlined appearance.

Although Woodley's style sits high on her head, it's a far cry from a stiff cheerleader ponytail. "We decided that a high ponytail would be appropriate as we didn't want to overdo it," said her hairstylist Jamal Hammadi. "She's such a beautiful young woman, and I wanted to celebrate that." Hammadi applied a shine serum before blowing out hair, then sprayed on the Hamadi Shea Spray ($19; hamadibeauty.com) to add extra shine. After a quick pass with a straightening iron, he gathered her strands into a high ponytail, keeping her center part to maintain a modern look.

Don't stress over salt-soaked hair. Try Mary-Kate Olsen's textured 'do if you hit the shore, but don't have time to re-style. Olsen's hairstylist Charley Brown separated her hair into four sections, and after adding texturizer and sea salt spray, he shook out her strands and twisted each section into a piecey bun. "Rub the silhouette of the hairline to bring out the baby hairs and intentional flyaways," Brown said. "This gives the style a romantic, undone feel."