When you have brown hair and blue eyes, natural makeup looks best when you find the right brown/light pink tinted lip color. If you go without color, your mouth looks washed out. But with that invisible color on the lips, it makes everything else pop! It's like wearing nude shoes with a simple dress. It changes EVERYTHING.
Eyeliner. Notice how there's a hint of blue on her lower lids...and she has blue eyes. Traditionally you go opposite in eye makeup colors (blue eyes get neutral colors, brown gets jewel tones), but I have blue eyes and do this on occasion. It really makes them pop!