the best is to correct mistakes after students’ speech: you listen, fix the mistakes have been made and after that you discuss it altogether, because interruption makes feel frustrated and they lose the motivation to produce speech.

@Alice , what I´m trying to say is not correct but find a way to show your student she / he is making a mistake without telling him/ her.

If a teacher is correcting me all the time I would stop taking that sort of lessons.

I already have my wife telling me about all my mistakes : )

I'll be happy if the teacher corrected me

Personally, I prefer being corrected immediately. I believe that repeating the incorrect phrase or intonation for several times makes it a habit; and there is nothing more difficult than changing a bad habit.

I really like to be corrected. And it doesn't matter if it's immediately or after speech, for me it's important just to happen. There is no better way to learn than from your own mistakes.