Use White Eyeliner

Hilary Duff keeps her look fresh, shimmery and accessible. The best way to achieve a similar shine?

A few swipes of iridescent white liner underneath the bottom lashes.

It will add definition in the subtlest way, both opening the eyes and drawing attention to them without being vampy or overbearing. Just be sure to choose a sheer formula with a hint of sparkle—matte versions can make your eyes look chalky.