While good for many things, glamour magic's most powerful application is illusion (those of the House of Eiluned are most adept at this purview). Illusions are different for the fae than they are for mortal creatures. Elsewhere is largely made up of a substance known, colloquially, as glamour. Glamour is an ethereal, mercurial thing, much like dreams. For, in reality, it is similar to dreamstuff. A complicated thing. While richest and most potent in Elsewhere, glamour is found in any place there are things that sleep and dream and feel and bleed. Illusion magic takes glamour and shapes it, bending it to the will of the caster to create an image, scent, or other tactile sensation.
Unlike mortal illusions, glamour illusions are visible to anyone that looks. As if they were real. Always, however, there is a single thing that gives away the lie of their existence. A perfect apple may taste like a pear, a man may be dressed finery except the insides of his pockets may betray the rags he truly wears... etc. And if you do not know the illusion to be false? It can still cause you harm. The key in avoiding injury or even death by illusion is the knowledge that it is, in fact, merely an illusion.
Simple illusions (e.g. the sound of music, images of things that are clearly naught but images) take very little time to create. A flick of the fingers and little more. Anything more complicated requires concentration. The physical scope of the illusion is irrelevant, the details are what is more the point. A strawberry, fully edible, perfectly detailed save for a single silver seed would take as long as a raging wildfire that spans miles.
The longer a fae spends on crafting the illusion, the smaller the tell (the thing that reveals it to be an illusion). Some fae have been known to spend months or years creating illusions. Some grand, some insignificant (an immortal creature has little use for time, after all), but all such illusions are detailed and exquisite.
Another facet about illusions is that they may be bound into an object and, when completed, be triggered by a specific event or word. Then the illusion will be unleashed. The illusion must then either run its course or the item it is stored in must be destroyed in order to cease it. If not bound into an object, the illusion may only be stopped by the one weaving it, or by rendering the one weaving it unconscious or dead.