Job in management consultancy

Hello, I qualified my group 1 CA final and Written exams for group 2 this may. I have my interests in Investment banking,management consultancy advisory areas.My articleship experience is mostly internal Audit.I want to join in one of the big 4s,Can someone guide me as to how to approach them as I dont have any references. Also can I know which firms/companies are best suited for my areas of interest other than big 4s. I am from Bangalore. Thanks