Get multiple quotes, references(call them and ask to see their work), google research and check BBB. Any decent contractor who does great work will be busy. Guys who can do it quickly asap that's a red flag. Have an agreement in writing and have milestones(framing complete, electrical, plumbing) and payments due at certain milestones. Use an actual licensed electrician not their guy( unless they are willing to provide his credentials). Check credentials against the ESA list of licensed electricians. A building permit would also ensure another level of inspection. Ensure that inspections are completed and signed off by inspector if you go that route. All people used eg(HVAC, plumbing, electric) should be red seal accredited trades people. Take your time and be extremely diligent and wary.