Texture: Makeup artist Sue Devitt recommends looking for an undereye concealer that contains the flexible plastic polymer nylon 12 (like Fresh Absolute Concealer or IsaDora Perfect Coverstick): "It ensures that the concealer will stretch with facial movement."
Color: A concealer a little lighter than your skin tone, with a slightly golden (or apricot, if you have dark skin) cast, will minimize dark circles. For more camouflage, makeup artist Matin Maulawizada uses a color corrector first. A bright yellow (Physicians Formula Gentle Cover Concealer Stick in Yellow) further conceals blue-tinged darkness on pale skin, orange (Bobbi Brown Corrector in Dark Peach) is an antidote to bruised tones on olive or dark skin, green (Couvrance Green Concealer Stick) counteracts redness, and mauve (Make Up For Ever Camouflage Cream in #18) softens very sallow tones.
Application: Use a small, slightly tapered brush, and start at the inner corners of the eyes. Work your way out, applying concealer only over dark areas. Concealer can accentuate the lines at the outer corners, and you probably don't have discoloration there. Set the concealer by dabbing on top a touch of translucent powder (Bare Escentuals i.d. Mineral Veil) with a small puff or shadow brush.