Photo by Courtney Rhodes
The undertone of your skin plays a key role in determining which makeup colors will look best on you. If you have a warm undertone to your skin, warm shades of makeup will be the most flattering on you whereas if you have a cool undertone to your skin, cool makeup colors will look best.
An easy way to tell whether the undertone of your skin is cool or warm is by looking at the veins on the inside of your wrist. If they look green, your skin has a warm undertone. If they look blue, your skin has a cool undertone. If they fall somewhere in between green and blue, your skin probably has a neutral undertone. 
Another important thing to keep in mind is that it doesn't matter how dark or light your skin is. There is a common misconception that people with darker skin have warm undertones and people with lighter skin have cool undertones. However, this is definitely not the case. It is possible to have pale skin with warm undertones or dark skin with cool undertones. 
For warm skin undertones:
- Look for a foundation that has yellow undertones rather than pink undertones.
- Choose bronzers that have golden or orange undertones.
- Look for lipsticks in shades of coral, champagne, raisin, bronze or warm red.
- Try eyeshadows that have orange, yellow, gold, or green undertones.
For cool skin undertones:
- Find a foundation that has pink undertones rather than yellow undertones.
- Look for a bronzer that has neutral brown undertones rather than orange undertones. However, be careful since bronzer can look dirty on the face if it is too brown or gray.
- Lipsticks in shades of pink, burgundy or cool red will be most flattering on your skin.
- Cool-toned eyeshadows in shades of blue, plum, purple or pink are a good option.
For neutral skin undertones:
- If your skin has neutral undertones, you can pretty much wear whatever makeup you want and it will look great on you.
All three skin undertones look great in neutral shades, as well. Brown, black, gray and navy blue are equally flattering on everyone.
If you are having trouble determining whether your skin is warm or cool, you can always go to a makeup counter at the mall to find out. A quick consultation can help you determine which colors are the most flattering for your skin.
Check out this video for lots more great advice on figuring out your skin undertones: