When it comes to making the right choice of liner for your eye color, things can sometimes get confusing! My basic suggestion (not a rule by any means, as rules are made to be broken!) is to pick an eyeliner color that is opposite your eye color in undertone. For example, when it comes to brown eyes, most people want them to look as rich as possible. Using blues and charcoals will help brown eyes really stand out.
For blue eyes, you could certainly use a navy liner BUT I like using a black/brown liner to really brighten blue eyes. I have green eyes which puts me smack in the center of cool and warm. So which color do I choose? When allergy season hits (bear with me) and my eyes are red the green pops like crazy! That tells me to choose a liner with a red undertone, like purple or a light brown. I like Precision Eye Pencil in plum.
Those of you with hazel eyes are lucky! You can use any liner color and it will bring out different shades of your eye color. Browns will bring out the yellow. Blue will bring out the brown and purple will bring out the green.
For our grey/blue eyed friends, using black liner will sharpen the color of your eye and really make them pop!