Using Gimp To Bring A Clients Vision To Life

This is the building in its original form. It has been passed around the past few years and no one has been able to make a viable business out of the joint.

To bring a new vision and to help break a language barrier with the new owner a partner and I wanted to bring it to life digitally .

Not really big with using photoshop I ran to the comforts of gimp 2.

Any advise would be nice into how to get a more realistic look out of it. Just a small side hobby.