There's one hair product that's used on everyone from Zendaya to Benedict Cumberbatch and Jacob Batalon: Hask Argan Oil Repairing Shine Hair Oil ($7). Flowers said just a little bit adds "texture, separation, and shine" to every hairstyle. "It helps with the humidity, it helps keep the ends healthy," she said. "Especially shooting in Atlanta where it can be humid, it really gave me a lot of control."
The best part: it's under $10 and can be found at the drugstore.