I was rejected after the ISB interview 3 years back.
Now that I have your attention, I wanted to highlight what I did wrong during that time, and thus what you should avoid:
1.
Keep your calm during the interview: I didn't. I was jittery and nervous. Since I was one of the younger applicants (2 yrs work ex), I think the interviewers were testing how I could handle stress.
2.
Don't over-prepare: I know it's counter-intuitive but don't spend too much time preparing - this is not the UPSC. If you over-prepare, your mind gets tricked into believing that this is some impossible task. You need to convince yourself that it's just a 30 min conversation.
3.
The 4-5 "must-prepare" questions should be spot-on: This is not contradictory to point 2 above. The Why MBA/Why ISB/Why now/Goals/Introduce yourself will be asked and you have no excuse not to prepare for these. But (hopefully) you already know the answers to these.
4.
It's not the end of the world: I got rejected and I won't lie - it sucked. Now, things aren't that bad; (caution: bragging ahead) earlier this year, I got accepted into Wharton, Kellogg, INSEAD and withdrew after interviewing from Booth and LBS. You should definitely give it your best shot but bear in mind that ISB (or any other school) is not a necessary or sufficient condition for success. Sure, the stakes are high but you need to avoid the paranoia by accepting that there will be things you can't control.
I'll stop my rant now. Reviewing this, it seems more of a Philosophy 101 discourse than a b-school interview guide. I feel old.
Feel free to reach out for any specifics.
Abhishek.