Know what you want before you get estimates.
First thing any home owner should do is create a plan and some ideas. This gives you a foundation to build your ideas vs having a contractor tell you their ideas. Remember your ideas are what's being designed and discussed. This allows you to control cost with unneeded recommendations you may end up not liking.
Verify insurance coverage
IT's extremely important for you the home owner to know what is covered by your homeowners insurance and what is covered by your contractor's business insurance. ServiceJoes.com recommends you get a copy of the company's insurance policy.
Don't pay more than 10 percent of the job up font.
Most jobs require only 10-20% materials cost. ServiceJoes.com recommends you avoid getting hustled out for money or have your money finish someone else's job. The contract should include a payment schedule and triggers for progress payments with all job estimated and completed.