Dear Anonymous A,
First, congratulations on your 3 offers! That's a great outcome. What I would suggest in order is:
1. Celebrate your success: you have prepared for these interviews and you deserve some celebration with your family and friends, so go for it!
2. Prepare the hard skills:
- Financial modeling: Valuation models, basic analysis (pivot table, validation, formatting)
- Powerpoint: as you are transitioning from T2 to MBB, I think you already know this by you can focus on the messaging techniques, the formatting and the storylining. One exercise that I advised to junior consultants is to take any subject (really anyone) and draft 10 slides on it after 2 days of work (of course if you have some time) and go present it to someone outside the industry and a partner who is willing to spend 20 minutes on feedback. That might be helpful
- General knowledge: reading is key. If you think you can bring expertise in a certain field, I would recommend going through the market research / reports and get up to speed in the field you want to work in (let's say payments, you should then definitely check fintech forum lists, payments update by CB Insights etc)
3. Work on your soft skills:
Again, this should not be new to you as you are transitioning but I would really recommend you to work on those 3 skills, especially for BCG: assertiveness, empathy and team work.
- Get (a) mentor(s): maybe it's ont of your interviewers, or the first manager you will have, or else. Anyway, you should work on getting this network as soon as you get into the MBB you will choose
- Get a buddy: when you will start your journey at any MBB, they will assign you a mentor and a buddy. However, try to find someone who will give you the tips and tricks to succeed in the first month. As you are transitioning from another consulting firm, that could be very frustrating to get up to speed to consultants that have lower seniority than you but who are "at home".
4. Other tips:
- Focus on giving your best on the first two projects to set confidence in the office and be a go to person
- on the second semester, after you built your professional brand, start building your personal brand, by getting involved in the office activities
- After one year, you will feel at home
Anyway, again, congratulations! Don't forget it is quite rare to get all 3 of the MBBs, so good job and best of luck for your career!