It's true of makeup and clothes, and it's certainly true of hair, too: The wrong hairstyle can make you look older than you are. Dated 'dos that call Farrah Fawcett to mind and sprayed strands so stiff a tornado couldn't take 'em down - those are just two looks that can age you well beyond your years. Here, top hairstylists pinpoint the worst mistakes to avoid, and what to do instead.