There are many avenues an aspiring consultant can pursue to secure a referral:
As expected, the best way to get a referral is by leveraging your personal network. If you already have a relationship with a consultant in your target firm, then the hard part is done. Depending on the strength of your relationship, you could simply just reach out to them about your intent to apply, and they would be happy to refer you.
If you do not personally know anyone, then you can leverage the network of your colleagues, friends, and family. This would still be better than cold contacting these consultants. However, since these would be second-degree connections, do expect to put a bit more work into building up that relationship.
If you are from a target school, then you are in luck. Your consulting club and career service will probably organize multiple networking events throughout the year, particularly during recruitment season.
These events could be anything from company presentations to dinners and coffee chats. These sessions are usually more about getting you interested in the firm, but the consultants present are also keeping their eyes on potential recruits. In fact, recruiters may ask the consultants to present their observations of the attendees after the event. So, take this opportunity to ask insightful questions (for which you cannot find the answer elsewhere) and network with the consultants there. Finally, be sure to get their name cards and follow-up afterward.
If you are not from a target school or have already graduated, you don’t have to worry. Some firms regularly organize informational sessions that are open to the public. These kinds of sessions are increasingly common as the top firms realize that good talent not only resides in their target schools. Such sessions are usually similar to the ones in target schools. However, these sessions usually involve a stronger filtering process (usually a resume screen), so be prepared!
If you do not know any consultants in your target firms personally and recruitment events are not an option for you, then your only option is to cold contact consultants. The best way to find these potential referrers is via LinkedIn. You can use the filtering system on LinkedIn to filter for consultants from your target office, and, if possible, for alumni from your alma mater or previous companies, as these are the ones who would most likely refer you.
When contacting these individuals, take note that your objective is to set up a short call (of around 10-15 minutes) with them to learn about their experiences, and not to ask for a referral. After all, you are a stranger to them; they have no reason to refer you just because you asked nicely on LinkedIn.
Most of your outreach messages/emails will be ignored, but hopefully, a handful will convert into calls. Once you get into a call with a consultant, you now have to build a relationship with him or her based on common interests. Do not spend half the call pitching yourself (unless they ask, of course). Instead, ask questions about their experience choosing the firm or about the projects they have worked on in a domain that interests you, and then take it from there.
If you come off as genuine and client-ready, they may offer to refer you on the spot. If you feel that there was a strong connection but they did not offer to refer you, then you could ask for one indirectly. Alternatively, they may sometimes offer to mentor you, give you a mock interview, or even offer to schedule a second call or meet-up to answer any other questions you may have. Each situation is different, so you will have to play by ear and do whatever seems best.
Regardless of which avenues you pursue, remember that nothing in life is guaranteed. You might not end up with a referral at the end of the day, but if you managed to get on a call with a current or former consultant, then you should at least have gained enough content to tailor your cover letter to your target firm and make it stand out. That, while not a referral, could still help your chances of making it to the next stage.