Magic, Gramarie and Sorcery

Magic in fantasy typically falls into one of three major categories:

Magic as Alchemy

This is magic of the lone scholar, poring over ancient volumes of lore. He or she typically discovers something, or uncovers something, that makes the magical system of The Elders (or the Vanished Ones, or the Forgotten) available to them.

These magic users are secretive, jealous of their knowledge and prone to cryptic utterances and encoded notes. (It's worth noting that the historical alchemists wrote their 'laboratory notes' in a cryptic pseudo-code, with mythic creatures such as the phoenix standing for particular ingredients or processes. They did this so that rivals couldn't take advantage of their work to forward their own researches.)

Fantasies that employ this type of magical system are often set in a quasi-Europe of the Dark Ages. See Sean Russell's Beneath the Vaulted Hills.

... or as Technology

Magic is an advanced science, and is studied in Collogia, amongst one's learned peers. Our hero might be a rebel, eager to study forbidden magic, or exploring uncharted realms, but magic itself is a collection of knowledge that has benefitted from group endeavors.

Martha Wells' Ile-Rein novels fall into this category. Philip Pullman's fabulous fantasy trilogy His Dark Materials is another series in which magic is studied collectively.

... or as a part of Nature

Here, magic is something that some people are just born with the ability to do. It is preferrable that they be taught how to best employ their skills, because if they learn on their own, they might hurt themselves or others. Robin Hobbs' The Farseer Trilogy is of this ilk, with hero FitzChivalry FarSeer being taught only one half of his magical legacy, with predictably unfortunate results.

Mercedes Lackey's Valdemar books also views magic as an inborn talent, and those with the talent gravitate to the Heralds, keepers of the peace in the kingdom. It is interesting to speculate on the life and fate of a talented one who remained outside the Herald system, but to the best of my knowledge, this is something Lackey has yet to explore.

Pick a System and Stick to It

When constructing a fantasy world, it's important to find your magical methodology and then stick with it. It's conceivable to have a 'lone wolf' sorcerer in one part of your world who suddenly discovers an entire continent of scientific magic users, but the magic they use needs to be consistent. Lackey stretched the limits with her Heralds and Herald-Mages, with mere heralds having one or more talents such as telepathy or firestarting, and the herald-mages also being able to tap into the magical forces within the earth itself. Combining magical systems within a single work is for advanced magicians only - do not try this at home!