For the last two and half years I've been working on construction site, that has led to another smaller construction job. What I learned is you need to be keenly aware of what the contractor wants to see, and how he wants to see it. I'm no expert because many here have had a lot more diversified experience. One thing, DO NOT low ball a job, if you are cheap you won't be looked upon as professional. Make sure you can deliver decent quality photos and videos, contractors aren't looking for beauty shots, they are looking for work progression and the ability to inspect from the comfort of their office in some cases.
Selling point, the superintendent that I have been working with told me that our mapping, panos, and videos saved him countless hours by not needing to go out and make physical inspections. If you can help save a contractor time, you are saving him money, basically you need to show him the benefits of the service you provide.
As for real estate, may experience has been it is a waste of time, realtors normally don't want to pay squat. I have got a few good jobs from insurance companies doing aerial and standard photography and they basically just want point and shoot photos.