I've not hired any 'coach' .... but I've had a few good mentors.
First of all, what they teach in "business school' is how to function in someone else's large corporation ... NOT how to start, nurture, and operate your own business.
Second, most "development" seminars seem to be either businesses whose main business is either putting on seminars - or shilling their products (like insurance, etc.) The 'wisdom' that they offer is readily available in countless business books .... they just deliver it at a much higher price, with an over-paid cheerleader.
That leaves us with the avenues that are available, and that actually WORK:
The best is: find yourself a mentor. That is, work for someone who will show you the ropes. You didn't become an electrician overnight; it will take a similar effort to learn to manage people, grow a business, or operate a business.
Avail yourself of the numerous books out there on starting a business. Each will take a different approach, and address different parts of the whole picture.
I've said this before - and usually get snickers in return - but I still maintain that some of the most concise 'business advice' can be found in the various books out there, written by famous prostitutes. The ladies' books certainly are more interesting reads than, say, "Stallcup on Electrical Contracting!"
Join you local Chamber of Commerce, trade association, Rotary Club, etc. This will place you where you can learn from your fellow businessmen.
Your local community college can help you with the accounting, etc., courses you'll need if you want to avoid some paperwork disasters. Along the same lines, your CPA will also be a great source of guidance. It's about more than just number crunching.
Finally, there is the subject of franchising. Successful franchise operations make sure their members follow proven methods. The parent firm usually handles things -like capital equipment and advertising - that are essential to the business .... but are not 'part' of the business itself. Watch and learn.
Any franchise who limits their part to letting you use their name is a waste.
Again, the principles are universal, and are not dependent upon the nature of the product. Second to hookers, the best business advice I've received came from a convenience store.