Hello,
I am a new member and just read through this thread and decided to put in my 2 cents worth. You have received some very good advice so far, labor rates, hiring tactics, etc. I have been through much of what you are describing and I just want to say that you first need to decide "who" you want to be in this business. If you want to turn wrenches and fix cars, then your first hire should be someone to field the front counter and phone (as much as customers are needed, they eat away at you time like nobody's business), even if it is only part time to start. Someone who exudes a sense of trust and friendliness. So, where do "you" want to be? In the shop, or on the counter? You cannot be both effectively. If you want to eventually be the "business owner", you will end up being neither, but for now you need to decide if you want to work on the cars or handle the customers.
Next, if you intend to keep on doing big jobs you need to find a way to do the smaller ones, ($200.00 jobs pay the bills) possibly with a low-rise lift that can be placed outside a service bay for brake, tire and chassis work while you are still working on the engine jobs.
Don't try to take every job as a challenge. This is my biggest downfalls. You will end up spending way too much time on things you cannot bill for.
Know when to send a job down the street. Pride is one of the 7 deadly sins, especially for a business.
As far as more advice, I would need to know more about your goals. Do you WANT to do the physical work on the cars, WANT to talk to and build relationships with customers, WANT to OWN and operate a business? They are all separate things and if you try to do all of them you will wear yourself out and resent the very business that you own.
You CAN be successful as long as you know who YOU are in all of this.. You can work on cars at least part of the time, or work on the counter part of the time, and own the business too as long as you know that as a business owner your role goes way beyond that.
Just decide what you want personally and the business will be build around that.
