1) Since the story revolves around Delhi, Taapsee being a Delhi girl made sure she does her own styling for the movie as she was more aware of the trends and fashion prevalent in the city and this how she became her own stylist on set.
2) Taapsee plays the role of a victim in the movie for which the traced back to her college days when she faced a similar incident which helped her bring more reality into her character.
3) For the powerful impact in her voice the actress wasn't allowed medication despite of the fact that she was suffering from cold and fever. Taapsee was thus shooting even while she was ill as it was the requirement for the character.
4) The actress left everyone spell-bound on the sets as she gave many one take sequences and left the director impressed and also the veteran actor Amitabh Bachchan who later praised her for the same.
5) For the emotional shots in the movie Taapsee didn't use any glycerin as she wanted the character to be realistic and hence she actually cried on sets and felt the character to make it look real on screen.
Wow, now this is some real dedication to one's character and Taapsee has been amazing at it. If this is not enough then we don't know what is.