AsawariJ
Hi,
I received an invitation too.. Have you given any interviews before this? Please share some tips!

Yup, I have given and have been rejected in a lot of interviews

You can find
interview debriefs in my signature and also, you can search the last year's NUS thread to find more debriefs.
When do you have yours?
You should be prepared with About yourself, why mba, why now, leadership situation, team situation, long term and short term goals and why NUS.
This will form the major chunk of your interview.
All the best!