As an Ex Instructor I've seen most of MJ's tongue in cheek observations and then some. I left instructing because of the treatment.
I'd also add - Employ a good CFI and or CP. A person that the less experienced FI's can look up to and trust. Might also be an idea to decide whether you want a seperate manager and CFI or an individual who attempts both. 'Attempts' being the operative word. Very few experienced FI's make good managers.
And remember that whilst some owners may feel that a 'friendly' phone call about the recently departed instructor is warranted. Instructors tend to stick together and as you'll no doubt read/ have read on these pages they also have VERY long memories
IMHO any flying school is only as good as it's FI's
As my wifes grandfather used to say - 'Those who can do. those who can't teach' For whatever reasons some FI's stay teaching because they simply can't do anything else within the industry. That is by no means a dig at most instructors as they work hardest within this industry in the section that is least forgiving. Avoiding those less desirable individuals who talk a good flight is no easy task. Good luck