First of all, congrats on making it to the next round!
Focus mostly on the feedback you were given from the 1st round interviews-- always the most valuable starting point.
Then in my experience, I found great success in demonstrating my interest in the partner's perspective (eg. Did you start as an analyst, and if so, why have you stayed at X company for Y years? What has been the biggest change your company has undertaken recently?)
Hope this helps!