Keeping restroom stalls graffiti free is covered in a perceptive article at CMM. Of prime importance is the author's call to view the stall from the point of view of the user.
We train our folks to inspect their own work (as far as is humanely possible). When you've finished a cleaning job and put away your equipment, pause, put on your other hat and walk through the facility as would my daytime customer service representative, trying to find issues that the client might notice.
Sit down at the reception desk; you'll better see prints on the front door, or the spider web up in the corner. Same with the boss's office. In the restrooms, use an ultraviolet light to check for "=bodily fluids still on the wall next to the urinal, or behind the toilet tank. (Have never been able to figure out how the stuff gets there, but it does.) Finally, close the partition door and sit down on the toilet. You'll see the cigarette ash in the little corner ahead of you, next to the partition's side wall. And you'll see the graffiti, and hand prints, on the inside of the stall door.
A handy piece of advice from the article:
"One of my favorite graffiti prevention hacks is to apply a thin coat of mineral oil on the stalls where people are prone to write with permanent marker or ink. The oil is odorless, clear, and not easily detected by graffiti artists. If someone writes on the oiled surface, a general-purpose cleaner and a microdenier cloth should easily remove it."
One might even draw a bit of philosophy from the thrust of the article. Don't just strive to view life (as well as restroom partitions) from the perspective of the other; try to walk a mile in his shoes.