1) Look at what jewelry you look best in. Do you look best in gold? Then you need to get a red lipstick with an ORANGE undertone. Look better in silver? Then a red lipstick with a BLUE undertone.
2) Look at your wrist. Are your veins blue or an olive colour? (ya know, kinda green)
Blue = blue undertone red lipstick
Olive = orange undertone lipstick.
Note: If you look best in both gold and silver jewelry, then you can pull off either lipstick c: same with your wrist. If you can’t even see them very well, you can also pull off both c: