"Select A Contractor That's Right For You!"
Look for a licensed contractor with at least 5 years of experience doing the type of work your project requires.
Beware of "fly-by-night" contractors who arrive in an unmarked truck or van, or who won't give a business address.
Don't fall prey to high pressure sales tactics or offers to do a job at half-price because "we've done a job nearby and have material left over."
Make sure the contractor you select has liability insurance.  Ask to see a copy of the contractor's worker's compensation policy.  You may be liable if a worker is injured on your property.  Check your homeowner's policy to find out whether it covers you, and to what extent.
Will the owner of the construction company or salesperson you spoke with be supervising the job?  If not, who will be?  Will subcontractors be used?
Who is responsible for obtaining and paying for all permits and/or licenses - you or the contractor?
Does the contractor provide warranties on materials and his workmanship?
You must have a contract in writing to define the responsibilities of all parties involved!
Your contract should define how the contractor will charge.  Will there be a fixed price 
regardless of all cost overruns or savings?  Or, will you be billed by the hour for labor and separately for materials?
What type of payment schedule is expected?
What is the contractor's change order policy?
Get a least 3 bids for your project and review them carefully to make sure they included everything you want.   Keep in mind that the lowest bid may not necessarily be the best  bid, and that an unusually low bid may be cause for concern.

These organizations can be helpful in selecting a contractor:

Nassau County Consumer Affairs - 516-571-2600

Suffolk County Consumer Affairs - 631-853-4600

NARI (The National Association of the Remodeling Industry) - 631-673-NARI

LIBI (The Long Island Builder's Institute) - 631-232-2345