These sites offer some GREAT tips too. For example, did you know...
Contractors specialize in a specific service such as landscaping, painting, plumbing or roofing and usually provide both labor and materials. General and residential contractors -- builders -- oversee entire home improvement projects and home building, coordinating subcontractors, workers and supply deliveries.
The Five Essentials of selecting a contractor:
1) Do not be forced into signing a contract during the initial visit and ask if
they are fully licensed or registered in their city and state.
2) The contractor or home service company should be fully insured (worker's compensation, general liability, property damage). Make sure they are!
3) Check for a clean complaint record with your BBB.
4) Determine if they are an established business with a good reputation.
5) And, ask for references from previous clients. A reputable contractor will certainly have a nice portfolio with solid testimonials.