Start by looking for recommendations from family, friends, co-workers, etc. You might also consider other sources such as Yelp, Angie's List, or a local hardware store to find local professionals. Of course you have to know what you want and who you need for job. Once you have names and "before" you schedule estimates, visit the Arizona Registrar of Contractors website to make sure the person/company is licensed, bonded, and in good standing.
The link for Contractor Inquiry is: http://www.azroc.gov/roc/contractorsearch.html
Good luck with your project!