Most trades are licensed through a state governmental agency such as a "home improvement commission". You'll need to find the agency in your state and verify that the tradesmen is, in fact, licensed and in good standing.
You want a handyman that can provide a wide range of services. Specialization, in this case, is not the ideal situation. You want to be sure that they can perform a wide range of services.
Do you work out of an office or another permanent place of business?
Working out of a pickup is not indicative of someone who is serious about his business. You want to make sure that you are dealing with someone who is credible and reputable.
Can you provide me with three references from your previous customers ?
You may or may not contact the references (you probably should speak to at least a couple of them), but his willingness to produce the information speaks to his credibility.
What is your schedule and availability?
How long do you estimate this project will take?
Will you order the necessary supplies and materials or do I need to purchase them myself?