A good color means natural. Look carefully at a fistful of hair in the mirror. See how each strand has a different tone? Perhaps even different colors on one strand? These are the natural striations that Mother Nature gives each head of hair to work with natural lighting. A good "color job" must duplicate these natural highlights to be effective.
When you use the services of a real professional, go to the appointment with an open mind. You may have your heart set of pale blond, but if the colorist can prove to you that a deep strawberry is really your best shade, listen to her. She is trained to match color with skin tone. She knows what will work, and what won't.