Have a plan or design with specifications.
Verify name address and telephone numbers.
Verify how long they have been in business.
Verify license and insurance are current.
Look at photos of like projects completed by contractor.
Contractor must show interest in your project and display a positive attitude.
Verify contractor uses top quality products designed for your applications.
Verify contractor’s reputation (BBB, Chamber of Commerce, local suppliers, other contractors, past clients, etc.)
Get a written contract that is clear, complete and firm, stating all materials, work to be done and amount to be paid with pay schedule.
Never pay more than 50% up front and never give final payment until job is 100% complete and you are satisfied.
Get a start date and a completion date.
Make sure that everything you and your contractor have agreed to is in the contract.
Make sure all prospective contractors are bidding the same job. (Having a plan helps to ensure this)
If you find your favorite contractor has a poor credit history but excellent workmanship, you may purchase all materials yourself and contract labor only. (Give no money up front in this case.)