Think of the behavioral interview as a standalone FIT interview. The preparation is just like for the FIT part of other consulting interviews. Go through the typical questions, prepare your stories and practice delivery infront of a mirror.
For the technical interview, I would suggest to reach out to your HR contact to ask them about specific guidance on how to prepare. Given that it's AAG (Advanced Analytics Group), you can probably expect much more technical questions around data science and it's application.