As a professional screenwriter writing for Hollywood, I search out locales for my on location film scenes, while other scenes are shot on set builds to replicate perhaps an actual location. What makes a film set look real? Mainly the skill of the artists who design and build the sets, and then the lighting and photographing of the set. The set has to convey to the audience that what they are looking at is real. For example,  if the set is the inside of a spaceship, surface of an alien planet or any location that is purely imaginary or never seen by humans, the job of the set designer is easier because the audience has never been in such an environment. Traditional locales such as a restaurant, home or apartment are much harder because most viewers will have experienced those places and will easily know if set expectations aren't met.  A desert-scape will mostly challenge the set builders to make Styrofoam, plaster, and paint look like rocks and the cinematographer to accurately represent a single blazing source of light at noon. The most powerful agent in imbuing a set with realism would be the act of photography.

I've run on to a location situation where a set is being built to replicate an additional actual location of my Sci-Fi quadrilogy due to the fact that a group of futuristic-looking domes fell off of the island into the water from a hurricane and the structures will most likely be completely submerged in water by the time the installment is filmed. The set builders will have fun with this one.