Your hair color will look best on you if you take the time to determine if you have a warm or a cool skin tone, and then coordinate your selection of hair color accordingly. Cool undertones need to be matched with cool hair color, for best results. Likewise, warm undertones call for a warm hair color.
You have a warm undertone if you have a golden or yellowish undertone. Transferring that knowledge to the determination of whether or not your skin tone is warm may not be an easy task. Take a look at the veins on the inside of your arm for a quick, sometimes clear, 613 wig assessment. If the color of the veins appears somewhat green, then you may have a warm undertone. This phenomena manifests because the blue veins (carrying deoxygenated blood) combine with the color of the yellowish undertone to create the appearance of green. Blue plus yellow equals green.
If the veins on the inside of your arm appear blue, then you may have a cool undertone. This condition arises from a less yellow, perhaps pinkish, undertone above the blue (deoxygenated blood) vessels.
This method can only be used to make a good guess as to your actual undertone. Inherent in this simple method are too many variables for a definitive answer to be possible. For one thing, warm and cool are only approximate categories without clear boundaries. And what about neutral skin tone coloring? Many, perhaps most people, fit into this middle territory.
There are many books and sites online that attempt to help you find your correct skin tone category. Take the time to search out this information because your new hair color will look better on you if it harmonizes with your true skin tone.