Here is a list of things to look for.
1. Check out BBB and see if the company has any complaints.
2. Read online reviews. (check if they are real reviews)
3. Check out video reviews (if available) these are the most reliable.
4. Look for before and after cleaning pictures. (the more the better)
5. See how long the company has been in business for (the longer the better)
6. Check out the certifications (make sure they are certified in all the provided services)
7. See how long the employees have been working for
8. Ask hoe many techs will come to do the job ( 2 would be highly preferred )
9. Check out the website and see if its up to date
10. Ask for a referral list, and see what others have to say about the business and their services.