I’m trilingual (English, Italian and Urdu) and when I was in Italy, I used to be the interpreter in my school for new students who weren’t Italian, as most of them spoke English. I have experienced learning and teaching different languages (Latin and French as well), which allowed me to understand which methods work best, but also that not all methods work for everyone.
I usually focus on teaching them basic phrases and grammar first and strongly encourage them to listen to music in the language they want to learn or watch series/movies in that language with subtitles. Once the student has understood the basics, I start teaching exclusively in that language and encourage them to talk in it as well to build their confidence.