How they would start off, that was certainly the intriguing question for Mima. Mima was actually curious as to the reason that Marisa wanted to be taught under Mima. Marisa was probably nowhere near her level in expertise, but it was a law that a magician never revealed her true secrets, so Mima wasn't going to make Marisa a replica of herself. Sure she taught Marisa many of her spells before, but Mima's magic was centered around Astrology, the old study of the cosmos, as it was Mima's expertise. Unfortunately, Marisa had been starting to take on more Astronomy in her spells, the newer outside-world 'science' and rejecting the idea of Astrology entirely.
Of course, if Marisa simply wanted to be more powerful, that would have been more difficult for a human. It was easy for a Youkai, whom had high Od (internal magical power) to begin with, which is why some wizards and witches become so in tune with magic, they become Youkai, often the result of separation from others, or even training in Makai. Marisa clearly hasn't decided to do this, probably due to some sort of worldly bond, so that would have made it challenging. Youkai also had an edge as they weren't too different from Gods, in a way. While Gods gained power by faith, and how much humans put their trust in them, Youkai grew power by their fear, and how much they hated them. This was likely how youkai Witches and Warlocks were spawned. Anyway, Mima figured, the best way to figure out how to teach a person is to figure out how why the student wishes to be taught. Something a philosopher might say.
"Well," she said, "First of all, I can't imagine exactly why you want to be taught. I mean, sure you're far from my level, but you surely are skilled enough to protect yourself from Youkai, I'd imagine. Of course, if you need some help in fighting somebody or something, there's that shrine maiden," Mima hated bringing her up, because that would make people think about how she beat her, and Mima likely wasn't the only one, "But of course, I suppose you can always be better than her with my teachings..."