Hi
I've worked with a business coach, and one of my clients is currently working with one. My take on the process is - what concrete and specific objectives are you working on with them? I don't believe everything about running a business can be reduced to a number, like revenue increases or cost reductions, but there should be some sense of a concrete goal - like employee turnover, profitability, or even - reduction of hours you as the owner have to be involved in the business, ability to take a vacation, or the like.
Almost any community has several, but they don't necessarily advertise a lot or even network a lot outside of their circle. If you have a strong relationship with your chamber small business team, know people in BNI circles (or are in BNI yourself), these may be good places to look. Bankers and CPAs sometimes know competent business coaches as well.
A red flag for me is "We've got a system that will radically transform your business - you're so lucky you've found us because we have the secret." I tend to like working with people who acknowledge that much of consulting, coaching, and mentoring is the "blinding flash of the obvious."