Do you have access to Loopnet and Costar to look at Actives and Sold comps?? You might find a few in your local mls but usually they are not in abundance.
Go to
www.sior.com for some free info.
If you haven't sold this type of property before he will know by qualifying you in the first minute or two when you meet.Owners always ask me questions on the phone and when I show up to determine level of competency.
A KEY indicicator no matter the type of property is WHY are they selling to determine motivation and also will there be a 1031 exchange involved??Is the business for sale as well or just the building??
I would really co-partner on this as even if you land the listing you will probably make so many mistakes being your first the odds of it closing without help are slim.