Ask friends for recommendations. Check the papers to see who's doing business in the neighborhoods you're interested in. Talk to more than one agent until you find one you like, then stick with that agent. Create a team. In addition to a real estate agent, you'll need a mortgage loan officer, a real estate attorney and a home inspector.
Good advisors relieve a lot of the stress.
Get your mortgage loan first. That makes you more like a cash buyer, and it gives you better negotiating leverage. Know the market value of the house you're buying. That way, you know what the seller knows. If you start out with an insultingly low offer, it's harder to reach that win-win compromise for both buyer and seller.