Agents dislike it when you work with more than one of them simultaneously. It is understandable because if they were to spend all of their time and effort to try to help you find the best house, it would be devastating to see you buy from their competitor. There is a case when you would want to use two agents and that is when you are trying to sell your home in one place and looking to buy a house at least 10 miles away.
Your agent will want to do both, but it is important to find an agent who is very familiar with the respective area. The best way to find a good agent is by word of mouth. Ask around and find someone who has actually used the services of an agent. You need to find an agent who is a member of the National Association of Realtors (NAR), or a Realtor. One of the soundest pieces of advice about searching for a top-notch real estate agent came from a buyer who called agents in a town about 20 miles away from the place where he wanted to move, and asked them who they would want to work with if they were moving to the town he had his sights on. Since they were not competitors, they were willing to offer an honest opinion.
Another idea is to call an agent who has their name on a lot of real estate "for sale" signs for references. Also, look for the designations ABR (Accredited Buyer's representative), GRI (Graduate, Realtor Institute), and CRS (Certified Residential Specialist). Earning them requires course work and evidence that the agent has completed a minimum of sales transactions. In addition, make sure you and the agent get along. Hitting it off with an agent is not a good reason to work with one; however, not hitting it off is a very good reason to pass one by. There are a million of them out there. Find one who is compatible with you.
