What advice would you give a customer looking to hire a provider in your area of work?
Do your research on the company / person you are hiring. Don't be shy to ask for references. Try to find time to see prior work and quality of the job.
Be sure to state what it is you want or need clearly. The last thing either side wants is to have the work done and it's not right. If you can provide pictures, specifications, or blue prints.. even better.
If you already have a quote, or multiple quotes, be sure to review them thoroughly. If one company quotes a different product than another, the price could vary greatly just from one single item. Be sure to figure out what it is you want to use and ask for 'apples to apples' quotes. This will also insure you are getting a competitive quote.
Be sure you feel comfortable with the person you hire. This is a professional and border line friendship you about to establish. Does the person / company you are going to hire respect your wants, needs, property, etc?