Aggressively enforce the existing littering laws and instead of monetary fines make the law breakers do community service of "Picking Up Butts" or "trash" for 4 hours or 8 hours.
Make them wear a florescent vest that states "I'm a butt tosser" or a "McDonalds wrapper tosser".
You'll see less and less butts and trash on the side of the road.
The people that really piss me off are the cigarette chucker's on our highways, I hate it when the butt bounces off my windshield.
If I were a judge I'd have them walk from Worcester to Fitchburg picking up trash.