How to Master Flat Iron Waves Once and for All

My ideal hairstyle is loose, tousled waves — think effortless French girl on Instagram. The only problem? My hair is impossibly straight, and even though I'm a beauty editor and write about hair regularly, my own styling skills are basic at best. I'm essentially hopeless when it comes to braiding or using a curling iron.

But I finally mastered the undone wavy look a few years ago after TRESemmé global stylist Justine Marjan. Marjan, who counts Ashley Graham, the Kardashians, Olivia Culpo, and Kristen Cavallari among her clients, gave me the effortless waves of my dreams using a flat iron and a few styling products. Her technique was fast, and seemed easy enough that I'd be able to handle doing it myself.

Since meeting with Marjan, flat iron waves have become my signature hairstyle. I constantly get compliments on my hair from friends, colleagues, and the barista at my neighborhood cafe. Then, I'm asked how I do it.

While I know how to style my own thick, dry, straight hair, I wanted to get some general insight on how everyone else can do it, too. So, I reached out to Marjan to get her tips on curling hair with a straightener for every hair type and texture.

How to Curl Hair With a Straightener

• Pick the right straightener: Marjan says the type of flat iron you use is crucial for achieving this look. Her favorite is ghd's Platinum+ Styler (she's also an ambassador for the brand) as it has round, beveled edges and built-in temperature control that keeps the tool at a consistent temperature that doesn't damage hair.
• Prep hair and curl it with the straightener: Before getting into it, Marjan suggests prepping hair with a heat protectant product, like the TRESemmé's Heat Tamer Spray. Next, she says to separate the hair into one-inch sections and create S-waves by alternating pushing the hair through the iron and pressing the iron down and beveling it as you slide it down the hair.
• Break up the waves for a lived-in look: Once you've gone over your entire head with the straightener, use a small amount of anti-frizz cream, like Virtue Labs Correct The Polish Un-Frizz Cream, to break up the texture and give waves a lived-in look.
• Finish with hairspray: Lastly, Marjan says to finish off the look with a spritz of hairspray like TRESemmé's TRES Two Ultra Fine Mist Hair Spray all over to hold the waves in place.

Tips for Doing Waves With a Straightener on Curly Hair

When working with curly hair, Marjan recommends blowing-out the hair with a blow dryer and a boar bristle round brush, then go in with the flat iron.

For this texture, she suggests finishing the style with a hairspray formulated to define curls and control frizz. We're fans of Aveda's Be Curly Curl Enhancing Hair Spray.

The Bottom Line

This method is easy enough that even I can do it. But I ended up with dents instead of waves the first time I tried curling my hair with a straightener at home. Marjan tells me that this happen when you press down too hard on the flat iron or hold it too long on one section. "If you don't keep the iron in motion while gliding through each section, you can create creases and crimps in the hair that are hard to remove," she explains.

Even the simplest hairstyles have a learning curve, but along with these tips, the key is not overthinking it when you're going in with the flat iron. After all, these waves are supposed to look effortless.