Identify your skin tone: fair, light, medium, tan, deep
Identify your undertone: cool, warm, neutral, olive
Match concealer to your foundation for blemishes and spot coverage
Choose one shade lighter than your foundation for under-eye brightening
Use a peach or orange corrector for blue or dark under-eye circles on deeper skin tones
Use a peach or salmon corrector for purple or blue under-eye circles on lighter skin tones
Use a green corrector for redness and blemishes
Use a yellow corrector for mild discoloration and sallowness
Test concealer on your jawline or under-eye area in natural light
Check how the shade looks after it settles on the skin
Pick a shade with the same undertone as your skin
Avoid going too light under the eyes to prevent a gray cast
Choose a fuller-coverage shade for blemishes and a lighter, blendable shade for under-eyes
Adjust the shade for seasonal changes in your skin tone
Use samples or testers before buying when possible