2 Good tip for Interview is :
1> Only answer what & when asked and to the point ( Brief). if the question is did u walk on the moon, answer should be yes I did walk on the moon. they are not bothered what difficulties u faced while u walked on the moon, or lets say while coming back on the moon i also walked on the stars. This is not required. Only thing required here is yes i walked on the moon.
2> only carry those stuffs which you have submitted nothing new. If they wanted something , they would have instructed you by now. Carrying additional letters from friends, mummy, daddy, colleagues or neighbor wont help.
Coz like interviews and in real life, If you speak too much , it ruins many things, also providing too much extra documents might also ruin.
Only provide extra documents when u see the boat is sinking not when its still alive. extra burden can ruin it.
These r just my assumption and honest thought.
and also 2 x previous experiences of Interview in NDVO. ( my younger brother and my friend).
I might be wrong every case is different. and many may seem to differ, its your file. u can think better.