I'm originally from Singapore, currently a private kids' Eikaiwa teacher in Chiba prefecture.
I understand the frustration over learning a 2nd language because I myself speak 2 languages, English and Mandarin Chinese, and now I'm learning Japanese and Korean
My method of teaching is to go with the flow. For the very basic, I am able to use simple Japanese to conduct the explanation. I don't use boring textbooks, I make my own simple and easy to read worksheets for my students so they can do self-study without forcing themselves to read tons of English words not knowing what they mean.