General Prep Tips
Start preparing for interviews at least 2 months before the first round. While it may seem like a waste of time to start this far ahead, it will put you far ahead of the competition and build your confidence for the actual interview day
Do not focus solely on case interviews while ignoring PEI. Case interviews are easy to focus on—there are many guides and sample cases, and it can be fun to solve them! Most candidates that I coach that have gotten in to MBB have done so on the strength of their PEI interview. You have to crack the case, but it is equally if not more important to come across as personable and thoughtful in your PEI answers.
Case Interview Tips
The classic starting text is "Case in Point" by Marc Consentino. I recommend reading through the beginning and focusing on chapters are 3, 4 and 5. My favorite is chapter 4, which focuses on the Ivy System and different case types. Make sure you understand these frameworks and are comfortable applying them to the cases.
Viktor Cheng’s book Case Interview Secrets and website Look Over My Shoulder are good additional resources for when you’ve finished working through Case in Point
Remember to practice cases with other people - Find experienced partners or coaches who can provide a good feedback, alternatively find other students also looking to get into consulting. Practicing with others is key to improving your performance.
PEI Prep
Look up the most common questions asked and practicing formulating answers. The most common mistake I see is interviewees not answering the question asked! Work on at least 5 or 6 strong stories that can answer various PEI prompts
Be very structured in your approach to PEI. It is important to convey a story with your answer and to do so in a concise and clear manner