Except a good web site is ok. Only use a contractor who uses his name in the title of his company, like me of course. I want a person with a big ego fixing things for me. Chances are they will take pride in their work. Try only to deal with the owner.
Employees come and go but owners seem to stay around a little longer.
Remember you are trying to develop a relationship. Never buy a special price service. There is always something else you have to buy. Ask what the hourly rate is on the phone. When they arrive tell him that you want to know the cost of the parts before they are installed.