I give private lessons at home for kids up until the A-Level. I was lucky enough that my current students are all in 9th-grade and below.. so that the level is still manageable for me to teach them.
From time to time it gets pretty basic like Suki already mentioned. They all pretty much focus on grammer and writing, just like they do in school. So if you did that a couple of times then your an expert at it.
I'm looking forward to teach in Japan next year, hopefully to middle school
Gonna be an amazing experience for me.