Upon receiving an invite for a first round interview, I got a chance to do a practice case interview with a current employee. This was definitely helpful, so take advantage of it if offered. First round and second round interviews were two 45 minute interviews consisting primarily of a case plus a few questions about my resume. All four of my interviewers were engaging and picked interesting cases. Before the second round I asked my first interviewers for feedback. They told me to be more enthusiastic and to be more assertive in making assumptions, so this is my advice.