I love writing about witches, particularly practitioners of old-school folk magic. There's something about the cultural flavor, whether passed down through family tradition or discovered as a character explores her heritage, that makes the magic that much more fun. There are thousands of forms of folk magic, but here are few of my favorites...
In Latin America there are curanderos/as (m/f)--sacred healers who are often still Catholic. They channel magic to heal their community, sometimes assisting in births or deaths, protecting children and helping adults make decisions as a wise woman (or man) of the community. They are always ready with a charm to guard from ojo, the evil eye, and frequently are herbalists that can help with natural healing.
Brujos/as (m/f) are the "black" arts practitioners of Latin America. This can refer to any practitioner of witchcraft, and has a less friendly connotation than curandera. If a curandera has to heal someone from the evil eye, it's possibly a brujo caused it. Brujeria doesn't have to be evil, though. It is often (but not always) a religion in itself, using ancestor worship and relying on the gods and spirits of the Mayans, Aztecs, Incas and Olmecs. Often practitioners of so-called left-handed paths such as this are not evil, but they may have an ends-can-justify-the-means sort of attitude. They're the questioners who don't follow rules and would rather pay the consequences for mistakes than play it safe.
In Voodoo (a religion with several distinct branches that blends traditional African faiths with Catholicism) houngans (priests) and mambos (priestesses) serve the Loa, powerful spirits who work as intermediaries between Bondieu, the creator god, and humanity. The Loa are called in group rituals. A participant in the ritual will be possessed by a Loa. The Loa is identified and appeased according to their own personality, fed and feted, and then s/he can give advice and grant boons to the participants. Afterward, the Loa leaves the host and the ceremony ends.
Voodoo also uses magic, particularly in the New Orleans style. This is where voodoo dolls and gris gris bags originate using sympathetic magic to affect their recipients. Sympathetic magic is the belief that if you have an item similar to a person (say, a doll dressed up like him/her) or "contagious" to him/her (this refers to toenail clippings, locks of hair, etc.) you can cast a spell on the person through the item. The magic is stronger the more you have, so voodoo dolls stuffed with a lock of the person's hair or daubed with their blood would be more effective than just a doll. Sympathetic magic can be used in healing and other positive purposes. Those practitioners willing to use sympathetic magic to hurt another person are called bokors, and they can cause all sorts of magical mayhem--including the infamous evil of raising a zombie slave to do their bidding!
From European traditions, a hedgewitch is a solitary folk magic practitioner who may or may not practice religion in association with her craft. Hedgewitches are herbalists who perform scrying (and other forms of future prediction) and protective charms, such as blessing a house or crops and driving off curses. Some hedgewitches are willing to cast curses as well, so it's best not to get on their bad sides! Hedgewitches usually have a garden in which they grow their own magical herbs. Kitchen witches are a subset of them that create magic through food and home crafts. A hedgewitch often has a familiar (though not necessarily a cat) that she is intimately tied to. Celtic mythology is often the biggest influence on hedgewitches, though they can rely on any mythological roots.
Folk magic is often such an inherent part of culture that we forget we're doing it. Do you avoid walking under ladders, fear breaking mirrors or hope that black cat turns around instead of crossing your path? I know I do! Folks magic makes common life a more magical and fascinating place to live. I'd love to hear about forms of folk magic practiced in your area. Have any stories, charms or superstitions to share?