Selling your home isn't like selling a used TV or a bike...don't just unload your home to the first realtor that comes to your door.  Speak with a few before making a final decision.

When you are looking for or talking to agents for the job, make sure they are up to speed on what's going on in the market.  If you ask an agent the ins and outs on some property in the area, it might be a good sign if your agent has the info on the tip of his/her tongue rather than having to consult a database/computer to see what is up.

Also though when they 'interview' you, you'll probably want an agent that asks what you might consider to be 'tough' questions, perhaps about finances and the like.  It might seem a bit awkward at first, but it will make the process a bit smoother in the long run.