Who says you have to use black or brown liner? Try blue in a monochromatic eye look. Use navy blue to line the eye, getting thicker and winging outward as it approaches the outer corner. Smudge with a shadow in a similar shade. For even more interest, paint a color such as teal on the outer corner, between the navy lines. You can do this with any color as well; choose the shade that most complements your eye color.
An eyeliner design can naturally enhance your eyes, make a bold statement, or show off a creative look. Experiment with different styles to find what works for you.