Depends on the story needs. Either the magic system shapes the setting, or the setting shapes the system. Your call.
For example:
I have an over arching nebulous concept of "SOUL STRENGTH." Which is a logarithmic scale. So a 5 is 10 times that of a 6. So I can have someone be a 5.4 and a 5.5 and it actually is a substantial difference. This is basically your underlying power level.
On top of that we have the local magic rules which are dependent on location relative to the dark matter reefs (which inhibit magic), memetic feedback from the local populace, as well as if the universe in question has Time. Time being an energy source, not a fundamental aspect of reality. Some universes just have a rate of change, where as some have chronotons. If there is no time, then there is no past or future, only the omni-present now. Universes with time have all sorts of options other universes don't.
Once I know the aspect of the particular universe, I narrow it down to the planet and determine if the laws of magic were established upon creation, by the gods, or evolved over time, or a combination of the three. Then, I figure out if the system has sections, like typical Arcane/divine/psionic divide, or if it's spirit based, or if magic that only affects your own body is a thing (aura).
Once I have the mechanics, then I work out the society that has the magic. A practical society will just call it "Water Magic" or Aura Control" Then if it is OLD, then I mangle the terms. Water Magic becomes Wama. Aura Control becomes Auco. If it's a pretentious society with an arrogant nobility, then maybe it's The Aquanautic Arts. Translating the name into an obscure language works as well. I once named all the powers of a magic system in Conganese.
Just remember, there is no species of fish named FIsh, there is no type of plant named plant, there is no fetish called normal, and there is no magic system called power.