Recommended answers:
I wrote a textbook... / course book... / research paper.../ etc., about... (provide details).
I was awarded... (provide details).
My students became successful business people because they learned English in my classroom... My teaching was based on case studies (give details).
I applied the strategies that helped to improve their English... (give details).
There are many more possible answers... You can speak about awards, additional teaching certificates, participation in international conferences, methods of successful and effective teaching, ESL testing software that you used or created, etc.
You will find more ESL job interview questions with provided answers here...
