Is your thin hair lacking the extra oomph that thick-haired girls take for granted? Unfortunate, but understandable. Hair care is not a one-size-fits-all application, and the tips and tricks your full-haired sisters swear by may not deliver the same results on your finer mane. In fact, Matrix celebrity stylist George Papanikolas says there’s one major mistake women with thin hair make, and it’s undoing all of your best efforts for beautiful, voluminous hair.