Though this is really a matter of personal preference, here is some advice to help you decide.
Choose a warmer tone if:
• You have olive or golden skin tone
• Your wardrobe consists mostly of reds, oranges, browns
• You often accessorise with gold jewellery
Warmer shades will enhance red or golden tones in your hair.
Choose a cooler tone if:
• You have a rosy, pinkish skin tone
• You often wear pink, purples, blues, greens
• You mostly accessorise with silver jewellery
Cooler shades will minimise red/orange tones in your hair.
Choose a natural tone if:
• You have an ivory or peach-like skin tone
• Your wardrobe consists of a variety of colours
• You accessorise with both gold and silver jewelelry
Natural or neutral shades help to enhance your natural undertones.