Plan your project carefully. Clip pictures, draw sketches, write a detailed description. This will help you accurately convey to the contractor what you want.
Make a list of contractors. Ask your neighbors or friends for the names of reputable tradesmen. Contact material suppliers such as lumberyards, and ask for recommendations.
Get a minimum of three written bids for the project, but don't just automatically accept the lowest bid. A higher bid may be worth the price in better materials, workmanship and reliability. If you get a very low bid, the contractor may have made a mistake or forgotten to bid on everything you wanted. If they have deliberately low-bid, they may use cheaper materials or take shortcuts to make a profit.
Many areas require registration and/or licensing. If licenses are required in your jurisdiction, be certain to ask to see your contractor's licenses and be sure that it's not expired.
Ask for references and then check them out. Look at the projects and ask the previous clients if they are satisfied with the quality of work done, if it was started and completed on schedule.
Get a signed, written contract and be sure you understand it. One of the single biggest cause of contractor disputes is the written contract: not having one, having a poor one, or having one everyone ignores. A good contract should include:
Be wary of hourly, time and materials or cost-plus pricing where the final price is not determined until completion of the project. Although it may seem higher, a fixed price may give you the best protection and price. Be cautious about up front payments for more than 15% of the contract price. The schedule and criteria for each payment should be clearly defined in the contract. Any payments should be not be required on a certain date, but correlated to work completion. Do not pay cash. A reputable builder will ask for a check.
Make any changes to the project in writing with a "work order change" to avoid misunderstandings and surprises.
Keep pets and children away from the construction site. This will ensure not only their safety, but also that of the workers. In addition, it helps keep the project on schedule.
Inspect the work regularly.
Pay directly and promptly according to the contract.