1. The Contractor will show up on time if they are responsible. Did your contractor show up on time? If he/she didn't how can you expect them to get your project done on time?
2. Does your contractor have pictures of the work that they have done? Do the pictures look good, or is the work shoddy and not up to par? If the pictures they are showing don't look right then how will your project be any different?
3. Do they have good reviews Online? If the contractor has a lot of bad reviews on the world wide web, then you might want to pass them up for a more reliable contractor.
4. Did the Contractor ask for more than 50% of the money up front? Personally I think that anything more than that is too much for a Deposit and should throw up red flags.
5. Ask to see some of their work in person. If the contractor is hesitant then that is a pretty good sign that they shouldn't be trusted.
6. How is this contractor communicating with you? Can you be heard clearly? Is the contractor listening to you, or just telling you what they want you to hear? The project is for you not for them. If they aren't listening to what you want then they are most likely not the contractor for you!