Typically, a contractor that has been in business for at least 10 years or more is a more reliable choice. However, it isn't always safe to assume that the age of a contractor's license represents how long the company has actually been in business. Sometimes a contractor's license has been purchased. Ask for a proof of incorporation date to verify how long the firm has actually been in business.
Request information from the Contractor's State License Board at (916) 255-4041, and the Better Business Bureau (BBB) at (619) 496-2131. You can obtain the contractor's complaint history, and see if they have any citations. This information is available by fax, mail or on the web.
Ultimately, make sure you have a clear contract, and the specifications are on the blueprints in understandable lay terms. Be apprehensive of any contractor who is vague, or won't put his promises in writing or doesn't do customary up front work… plans, specifications, or a written proposal.
Secure a total commitment to customer satisfaction. There are lots of moving parts and people that are key to successful home remodel. Make sure you are kept well informed, and any concerns are handled quickly.
Take whatever time you need to check and double check the contractor's references of recently completed jobs. Any reliable contractor will be more than happy to provide you with such a list.