The first interview was conducted on campus and was about 30 minutes. The questions were less (but still a couple) behavioral (tell me about a time when ...) and geared more towards personality, like a conversation. Very laid back. We began by introducing ourselves, then talked about my interest in EY and specifically the field of accounting and the position for auditing. Next, our conversation brought up topics about how my skills, experience, education and leadership (from my resume) communicated to the company and position. I highly recommend aligning your goals and visions with those of the company, research areas of interest and how EY has participated in these projects (search on reuters.com). Network with as many current employees as possible. Talk about those relationships to demonstrate your relationship building. Know the industries they service at the specific location you are applying.
The second interview was a full day at the office (breakfast and lunch provided). We began with a presentation, then had three 1:1 interviews with senior managers. Each interview had a topic: Leadership, Career Development, and People. In the first interview about Leadership we focused on skills and attributes for the position. Here's where you focus on selling yourself, tying in your experience and how that communicates to the position. The next interview for Career Development we talked about my future career goals, the five and ten year plan. We focused on training opportunities and continual learning, the interviewer shared information about EYU (web based training) and on-the-job training. The last interview we talked about People. EY is committed heavily to diversity and inclusion, focused on POSITIVE group work/ team-building experiences, and those that were not as positive and how you prevailed in redirecting the project and ultimately have a positive outcome (specifically YOUR involvement). We talked about the team environment and communication styles, understanding differences and how they can be beneficial to enhance the work environment.
Know their values: "People who demonstrate integrity, respect, and teaming. People with energy, enthusiasm, and the courage to lead. People who build relationships based on doing the right thing." Align your selling points on these values, focus on those areas of your experience in which (if asked) you can give a specific, detailed example.
Also, ASK A LOT OF QUESTIONS! This demonstrates your interest and enthusiasm. Come prepared with questions and also jot down interesting information from the presentation at the beginning and touch on them in your three interviews.
Lastly, do not over prepare. Refrain from sounding like a robot or too informed, remember it's an internship, they don't expect you to know everything, and the interviews are going to take their own course - like a free flowing conversation.