“Give me a head with hair,
Long beautiful hair,
Shining, streaming, gleaming, flaxen, waxen hair…”
Hair is ubiquitous. It crops up in mythology and fairy tales, it appears in a hundred different colors, styles and permutations, and I don’t think I’ve read a romance which didn’t provide at least some mention of it. It’s a source of power, a mark of heredity and one of the ways to spot a Mary Sue—her hair is likely to be overpretty or overdescribed. Usually both.
Minus Clairol, hair occurs in a small range of hues—blond, red, brown, black, grey and white. There’s a lot of room for variation within these colors, but in a fantasy characters can have Ramona Flowers hair with streaks in it—if there’s a good reason for them to have such hair.
Unusual colors might also affect how seriously the characters are taken. If everyone has hair like Rainbow Brite’s horse, the story might come off as a parody. I’d pick just one out-of-the-ordinary color, or at the most two (say, different colors for men and women).
As for natural streaks in hair, there’s a genetic condition which produces this – Waardenburg syndrome, which also causes mismatched eyes. A group of characters distinguished by a white streak in their hair is the Mallen family of Catherine Cookson’s novels, beginning with The Mallen Streak.
Hairstyles are a good way to show people’s occupations (monks, soldiers and prostitutes will all wear their hair differently) or age. For instance, girls wear their hair in braids but ladies put their hair up. Complicated styles might also be a sign of social status, because only rich people would have the time or the luxury to have their hair teased into various shapes a la Queen Amidala.
And in A Game of Thrones, Dothraki men braid their hair and cut it off when they lose a fight—so the longer a man’s hair is, the better.
People can wear pretty much anything in their hair, and often do. Ribbons, flowers, jewelry, chopsticks, berries, seashells, cakes of scent (in a hot climate, these will melt slowly) and even stuffed birds.
This is a good way to hint at social status too. At the start of Jean Rhys’s Wide Sargasso Sea, Antoinette’s braid is bound with string, but later on it’s tied with red ribbon, to show that her family’s fortunes have improved.
Samosn’s hair supposedly gave him great strength as long as it wasn’t cut. Though now I’m wondering if “hair” was a euphemism for something else.
And the gift Galadriel gave Legolas was a bow strung with a strand of hair. The color of hair could also be an indication of a person’s ability, though it might be best not to go for the cliché of fire-mages having red hair.
Finally, what’s your favorite hair color? I like black or brown for most of my characters, but the one which most fascinates me is red, especially if the person has green eyes. To me, that’s about as exotic as you can get.