Someone you feel comfortable with
If you just don't feel comfortable unless you doctor is a man, or a woman, or wears a lab coat, or wears sandals and beads, or whatever... then that is what you should look for. Granted you should never judge a book solely by its cover. If you give them a chance they might surprise you but ultimately once you have met with them they need to provide a certain level of comfort for you and meet your expectations of what a doctor should be.
Someone who listens to you
There is nothing worse than having someone totally ignore and invalidate everything you have to say. It's your health. You are the one that has to deal with it 24/7. You are the ultimate expert of you. The least a healthcare provider can do is give you their full attention whether it is just a fifteen minute appointment or two full hours. You know when someone isn't listening.
Someone that wants to help YOU
We all get into this field thinking we are going to change the world. But suddenly you realize the awesome responsibility placed on your shoulders. People want you to perform miracles. They want it to be easy, cheap, and have immediate effects. Everyone you know suddenly wants just a moment of your time to talk about their health. It's not uncommon to get burned out from trying to be everything for everyone. Doctors have to work hard at keeping that spark of excitement that got them into the field to begin with. If you think your doctor has lost interest in trying to help you then maybe it's time to find another doctor.
Someone who is willing to learn
Some doctors hide the fact that they need to go look up a disease or a remedy in a book. Personally I prefer the kind of doctors that pull the book out and let you read it so you can brainstorm together. Chances are you may have put more time into researching your symptoms than they have. Take charge of your health, find out all you can, and then make sure you have doctor who is willing to learn from you.
Someone who is willing to teach
Doctors spend countless hours trying to understand what is going on in the human body. The least they can do is take a few moments to help you understand yours. The very word doctor is related to the Latin word docere meaning to teach. Doctors should be teaching people how to be healthy. And as an extension, a doctor should teach by example. There is nothing worse than a doctor who is unhealthy.
Someone who cares about more than just money
Do you really need all those expensive lab tests? Do you really need to take twenty supplements per day? Do you really need to be referred to that specialist? Is your doctor willing to talk to you for a few moments even if you can't pay? Don't get me wrong. Doctors provide important advice and I don't necessarily think they should take a vow of poverty. But if money is the driving factor in whether or not they will help you... move on.
These are just a few of the things that I think make a good doctor. No doctor is going to be absolutely perfect for absolutely everyone. But take a moment and consider what it is you value in a doctor and remember that you are paying them for a service. Are they living up to your standards?