Best in one go was 340 for teaching a family for a few half days. I would wonder what I did wrong in a private if I didn't get tipped. In group lessons, especially kids, it's pretty much a lottery. I have been hungover and taught badly and got tipped well, and taught the best lesson ever and got nothing.
I am thinking that tips this season will be rubbish as I am teaching mainly aussies, and the aussie dollar has gone through the floor against the yen, rubbish!