This may not be the sort of answer you're looking for, but in my experience any good lawyer makes an awesome interview coach. Lawyers have all the skills necessary to perfect an interview IMO. I would rather hire one of them than a college prep company.
I feel like preparing for interviews is something I needed a lot of help with. I have been doing mock interviews with med school students, and have found them to be very helpful bc they have been through them before and know what they are like.