-Do not pay a contractor the entire price of the project upfront. Set a payment schedule with milestones that you both agree too and have this in writing. -Ensure your contractor has up to date liability and workers compensation insurance as well as appropriate licenses before starting work. They should be able to provide proof of this to you in a timely manner. -Be sure to get the scope of work for your project in writing. If you have to make any changes to your project while work is being done, get those changes agreed to in writing between you and the contractor doing the work. -Bids that are unusually low could be an indicator of lower quality work and materials.