a great deal of magical practice is predicated on the idea of sympathy. like effects or attracts like. becaue of this imitative actions form a bedrock of many magical workings. perhaps the simplest and most basic of these is the spoken word. simply put, to describe a thing is to imitate it. we can take this idea and expand upon it by saying that by describing an event or force we can evoke it, bring it into being via sympathy. this i believe to e the mos fundamental premise of incantation and words of power. by speaking a description of the desired result, you imitate that event and bring it into being. incantation can be used to manifest results directly, or as a means of directing energy into other aspects of spell-craft, such as into a talisman or other kind of working.
further, description and words of power can be used to imitate actions that a human being simply cannot do, even in token. such as “riding the lighting” or calling forth the concept of luck, healing and so forth.
it can be helpful wen composing such an incantation to remember the poetic logic of simile, analogy and metaphor, as well as to keep in mind the three subjects of what you want the spell to bring about, who or what you want it to bring about too, and the forces you wish to accomplish thus.