There are many articles out there that purport to help you choose a remodeling contractor, and this is one. But it’s a good one. Here are a couple of the points:

Ask for Referrals
Word of mouth-hands down, is the best way to find a qualified professional to tackle the job. Ask relatives, friends and neighbors whom they've had good experiences with. And ask what made it a positive experience, how the contractor handled problems and whether he or she would use the same contractor again.
Look at Credentials
With recommendations in hand, do some preliminary research, whether it's with a phone call or a visit to the contractor's website. Find out whether he or she holds all the required licenses from state and local municipalities, along with designations from any professional associations such as the National Kitchen & Bath Association, the National Association of the Remodeling Industry and the National Association of Homebuilders. Look for contractors who have invested in course work and passed rigorous tests to earn particular certifications. Be aware, however, that not all certifications are created equal. Do some homework and find out the requirements.