Things to keep in mind for GD/PI
1. Be humble, but not a beggar. Value your self-respect, everyone will respect you. Remember you are there because you deserve and have earned it.
2. Don't panic if you can't remember or answer something. Even the panel does not expect you to know everything. Don't use your waiting time by trying to remember or mug up answers.
3. Feeling tensed in the day of GD/PI is perfectly normal. A little bit of stress is necessary for good performance (it's called eustress). Just take care not to overdo it.
4. And last but most important - enjoy the process. Not every day you get the opportunity to compete for a job in the biggest bank of the country. Today is not the day of success and failure; today is the day of enjoying the game and performing your best.
So go ahead and give yourself and your interviewers a treat to remember.
All the best