1. You didn’t change the state of your hair. The best way to make a curl stay in hair that is not naturally curly is to change the state of the hair as you curl; this means you either go from wet to dry or from hot to cold. A wet set is more gentle and will always last the longest as the hair dries into shape. To do a wet set, wash and towel-dry hair, add your chosen holding product, then create your curls either with velcro rollers, your fingers, rags, or bendy rollers. Warning: Don’t use tongs or heated tools on wet hair, though. For quicker results, going from hot to cold will have the same effect, using hot rollers, steam rollers, tongs, stylers, or something similar.
2. You didn’t use any product. When you’re trying to get your hair to do something it doesn’t naturally do, you need to give it a helping hand. For hot tools, you’ll need a heat protectant, like Kerastase elixir ultime by Jade Jagger. Then choose a holding product that will give added oomph. If your hair has a natural wave, a curl-enhancing mousse, it will provide hold and staying power. But if you have straight hair, you’ll need something with more impact.
3. You let it drop before it’s set. One of the biggest mistakes we make when trying to create a lasting curl is to use a tool like a curling iron. These are great for ease of use and will give a nice temporary curl, but those curls will drop very quickly, especially if you have fine hair or very heavy, long locks. You can still use your heated tools for a longer-lasting curl, just add in one extra step: Clip each coil to your head right after you curl it, letting it sit on the head until it’s cooled completely. (Think pin curls.) This goes back to point number one: You need to change the state to set the curl. Speed things up with the cool-shot button on your hair dryer, and only shake the hair out when it’s stone-cold. Your curls will last twice as long this way.
4. You take your hot rollers out too soon. Hot rollers are great for retro waves and styles that require lots of body, but most tutorials tell you to leave them in for only 10 or 20 minutes. This is fine if you’re using them for volume or to smooth hair to prep for an updo, but if you want curls that last through a night of dancing, then you need to let those hot rollers cool completely—which in our experience can take up to a couple of hours for thick or long hair. Plan ahead and keep your rollers in as long as you can. And don’t forget to use a styling product!
5. Your cut is weighing you down. If you have particularly thick or long hair, you’ll probably struggle to get a DIY curl to stay in. The longer your hair is, the heavier it is and the harder it’ll be to get a uniform curl to stay. You have a few options to fix this: First, ask your stylist to cut lots of layers—especially around your face—to reduce weight and give the hair some bounce. You should find that these shorter sections curl better. Second, chop your hair a few inches shorter all around. The simple truth is that superlong hair will not curl easily if it’s naturally straight. Finally, if you can’t bear to face the scissors, try twisting wet hair into a bun (or two buns for very thick hair) and sleeping on it, or try headband curls. Dampen your hair, part it as usual, and put a narrow stretchy headband over your head so it sits halfway down your forehead and quite high at the back of the head. Starting from the front, take a section of hair from below and wind it up and around the band over and over again, adding more hair each time as you move around the head (as if you’re creating a big croissant with your hair). Leave this in for as long as possible—overnight is best. When you pull out the band, your hair will sit in bouncy, full curls.