Talk to a few different agents. Ask them all the same questions and see what answers you get. The main thing you want to look for is trust. If you don't feel that the agent is being honest and up front with you, but only tells you what you want to hear, then go to someone else. You should not feel like you are going through a sales pitch. You want to know what you should list your home for realistically and what their fees are. You also want to see how long their contract is for. If you are unhappy with results at any time, you want to be able to get out of an "exclusive contract" when you want to. You may also want to ask how many listings they currently have and have many actual closings. They should easily provide you proof of their success. Results is what you want, not empty promises.

Real Estate For Dummies is a better bet.

The #1 issue (beyond general competence) is DEEP familiarity with the small pockets of the local community you want to buy in. The #2 issue is longevity in that area. #3 issue is to avoid the part timers and dilettantes (aka ladies who lunch).

This applies to both seller and buyer agents.

If the two property locations involved (old house and new one) aren't BOTH in that same area of familiarity.. then you will need (be best served by) two agents.

I would skip the buyers agent and focus on getting a good seller's agent. If you're relatively familiar with the process of buying a house and you're comfortable going online and perusing the listings at Realtor.com, there's really no reason to have a buyers' agent. I think going through a realtor for selling is still valuable, if only because that means you get to list your house on realtor.com:)

My advice in picking an agent would to interview to find out what strategies the agent has to sell your house in a tough market. What qualities does the agent have over and above staging, setting a price, and putting the home listing on the internet to generate interest from buyers.