I say that to cast a spell, you first have to know what a "thing" really is, like fire, cold, sleep, mental states, a bone, flying, etc. As a spell user studies and learns the nature of more things, his spell knowledge expands.
In my game when a spell user is going to learn a NEW list I demand a research roll (using the SM research tables). Once the research is done (typically months, weeks if lucky/very high Em mod), the PC knows "thing" the list is based on. All additional spells on a list are variations on the theme of the "thing", so no further research is required, just exp and dev pts.
So spell users are always studying, meditating, doing weird experiments, etc. When a "thing" is so well known, alchemy allows the pattern of the thing to be imposed on vellum, swords, staves, rings, whatever.
For a spell to work, the esseance must be so well woven into the very fabric of the "thing" to make it appear that great empathy is required by some or amazing prescence of the mind. One takes a form of understanding it, while the other focuses more on not losing awareness of self being compared to "it". Essence users of course claim thats rubbish, no mage loses himself, but this misconception pervades menatalist users.
Channeling is simular in that the user must have TOTAL faith. He must believe and believe in nothing else, to the core of his being, that his GOD is rightious and the ONLY way, be it holy or unholy. In complete surender to his LORD, he gains the peity to weild his MASTERS power. The channeler only loves his LORD all the more because of it. Service is obedience, and obedience is service. Some Gods are more forgiving than others in how that love is expressed. So prayer, meditation, study of religious text, spreading the word and discovery of anything that brings Honor, glory, power and PROOF of HIS greatness.