Having worked with over 100 MBA students seeking consulting jobs, I've learned that the best outcomes are achieved when job-seekers work to develop their own style & approach to casing. There is no single formula to becoming a proficient interviewer, so it's important to tailor development and feedback to the individual who is going through the process.
Having spent four years at BCG, I also know the goal posts for candidates are constantly moving. The core skills that casing tests - structured thinking, creativity, and effective communication - will always be needed, but there is increasing nuance in how candidate are expected to showcase these abilities. Additionally, the fit portion of the interview continues to take on more importance for firms, which means candidates must be prepared to present the right pieces of their experience and personality in that section.
I'm always willing to use coaching time in whichever area the candidate would like to focus on (we could spend 60 minutes on frameworks or 60 minutes on behavioral prep, depending on identified need), but I always will want to use 5 minutes at the front of the meeting to understand candidate goals, firm targets, and approach to date. From there, we can work together to build an interview approach that showcases each candidate's unique strengths and personality.