1. Basic music theory (you must know the most basic theoretical knowledge of music)
2. Piano around level 6 and improvisational accompaniment skills (for every song in the textbook, you must Can provide accompaniment)
3. Elementary harmony (for some small chorus and other music that need to be arranged, it will not be difficult for you)
4. Basic skills of sight-singing and ear training ( The most basic ability to read and notate music)
5. Basic vocal skills (you must be able to sing, and not sing with your voice, but with method)
The above are professional skills.
In addition, you must have basic skills as a teacher. For example, you must be able to prepare lessons and be able to control the classroom well.
The above are the basic qualities that you should possess. Of course, it also depends on the grade you teach. In primary school, you mainly just make the children happy. When they were in junior high school, they started to be picky, and they might be looked down upon by students. In high school or technical secondary school, if there are music classes, they should be quite professional.