Mistake #2: You have shelves full of styling products.
If you're using more than one styling product in an effort to make your hair look fuller, your plan may be backfiring. "Mousse and gel and hairspray can give the hair lift for a few hours, but they also make it look stiff and sap its shine—a very aging combination," says Scrivo. If you have a well-layered haircut that's not too heavy at the bottom, you won't need to load up on styling products to achieve volume. One dollop of lightweight mousse will do the trick; once hair is dry, use a drop of silicone serum to add shine.