Inventing Spells
Synopsis
Inventing spells is the less efficient way of learning a spell, but on the other hand is the only way Magi can do it completely by themselves (that is without the need of a Teacher or a Lab Text.
Inventing Spells ArM5
The first thing to do is define the spell, what it does, what arts it uses, and parameters:range, duration, and target. That will define the level of the spell.