Stylist to the stars, Roy Teeluck tells PEOPLE that what differentiates the good from the bad in terms of treated tresses is a ''less is more'' approach. ''My salon specializes in the Balayage technique, which is easier to maintain,'' he tells us, referring to a method of hand painting highlights instead of using traditional foil. Pointing to Natalie Portman and Alexa Chung as those he thinks get the look right, Teeluck says brightening with tones that don't vary too drastically from your natural color is ''healthier for your hair, and can be customized to your desired look.'' Regarding Palermo's perfectly polished look, he says his senior stylist Michele Fury (who works on the former city star) considers many factors before adding depth with color. more... See more text