I believe in targeted preparation for interviews. Wherever you are at the moment we will start and work on your strengths and weaknesses while not letting the big picture out of sight.
I have interviewed and helped prepare candidates since my studies at HEC Paris and later at INSEAD and of course during my 7 years at McKinsey.
Preparation for McKinsey and the other big consultancies (and all interviews) should included a fit part and a case part. I have extensive experience in both and we can focus on one part of the equation or the whole picture.
I also went through the recruitment process for Investment Banking in London (my first job) and can highlight the differences in what the recruiters are looking for and how to adapt to that.