Be a good camper!
If you’re shooting at a natural location, such as a beach or a forest, when you’re all done, pass out trash bags and everybody wander around picking up trash and making it prettier. Not just your production’s stuff, but spread out. Make your group the Entropy Decreasing Group.
No, it won’t help the movie, but it’s a good thing to do.
We once acquired a location for a really tricky shoot after the owner saw how diligently we cleaned up another location where he was being an extra. He told me he never would have offered if he hadn’t seen us scrub the entire set down — after each take! (it was a tricky setup, because each take messed the set dressing up a lot and it had to be especially crisp and perfect at the beginning of each shot.)