It's not hard to make Mila Kunis' eyes look amazing. She maybe has the most gorgeous peepers on the entire planet. But there's a trick she uses upon occasion to make them look a little bigger and more sultry at the same time.
Her eyeshadow is winged out and up past her eyes. This is an old-school trick that opens your eyes and makes them look like they extend a bit farther. And because it's done with dark shadow, it also adds a touch of smokiness that's pretty hot. A one-two punch, really.
All you do to pull this off is load up a tapered-tip eyeshadow brush (or a Q-Tip, if you don't have one) with some shadow and brush up as if you were following the line of your lower lid up toward your temples. Easy enough, right?