To cover dark circles, choose a peach-toned concealer, which will counteract the bluish-purple color of your under-eye area. The general rule of thumb for picking a concealer for dark circles is the fairer your complexion, the more white or pale pink you want your concealer to be. If you have more of an olive or darker tone to your skin, reach for a concealer that has more orange or red tones to it.

Here, Katie uses a concealer with a hint of peach. She likes Laura Mercier Secret Concealer, $26, because it comes in all different shades ranging from peach to reds and oranges.

Blend in the concealer with a flat, firm brush like Real Techniques Oval Brush, $13. Katie prefers using a flat brush because you get the same pressure as a fingertip when applying, but less of a mess.

Gently tap over your concealer application with your fingertip to remove any excess and make it look more like real skin.

Now, apply your regular concealer (the one you typically use to cover redness or blemishes on other parts of your face) over the area. Katie's current favorites are Urban Decay Weightless Concealer, $28 and NARS Creamy Concealer, $29.

Using your brush again, blend your second concealer well. Blend it downwards (covering more than just the dark circles) to add brightness wherever your face needs it.