The most important thing for a real estate agent is to know a bunch of people, and get those people to recommend you.
I've had some horrific experiences with real estate people who are nice and make money, but in the end knew nothing and ended up doing all the work.
The best one I had, was very knowledgeable about the area, priced every offer correctly every time, and told us to when things were over priced and to walk away. I can say he was very good, but I don't believe he is raking in the dough (maybe he is, but he appears to be upper middle class at best).