It really depends on what's your objective.
1) If your objective is to to get a referral - the best way is to tell your background, ask if you fit and ask for their advice in prep.
2) If you are working on your fit interview prep - ask things like "why consulting"and "Why Company". It will be very useful to get the insider information about the particular office
3) If you are warping up with your prep - just do a mock case or test your fit with them