Disney did a lot of research on littering, actually. Part of the research actually involved handing people lollipops on the opening day of Disney Land in order to determine where to place trash cans.
A couple of things he discovered (about US culture, at least, but it would surprise me if it weren't exportable to other cultures to some degree):
People will generally carry trash ~30 paces before discarding it.
People will litter more once there's already litter on the ground. (Similarly, people will mess up clean bathrooms less than already-dirty ones.)
A couple of things from my experience working as a custodian at Disney World, which sees a large amount of foreign traffic:
People will, in fact, use trash cans. People will, in fact, continue stuffing trash into trash cans far past their capacity. People will spend two-three minutes trying to get trash into a totally full trash can when totally empty ones are twenty paces in either direction.
The same trash can will overflow ten times a day while the two on either side of it will require emptying about once a week.
Teachers are the messiest group of people, judging by conditions after their conventions. Christian student groups are the most likely to leave used condoms in the brush. Attorneys are the most likely to leave used condoms in the parking lot.
Smokers frequently have trouble telling the difference between stainless steel trash cans and cigarette receptacles, unless they're teachers, inwhichcase they use neither and make massive piles wherever they happen to be standing.
Men are -significantly- cleaner in public restrooms than women. (I was responsible for probably the only women's bathroom on the entire Disney property that was cleaned by a man; generally they're cleaned by women. This one was particularly remote and so both bathrooms were included.) [ETA: This should go without saying, but when I refer to men and women, I mean on average.]
A surprising number of people don't notice when they drop money on the ground. This can rescue the lunch of a custodian who forgot to pack a lunch one day.
Men are -significantly- cleaner in public restrooms than women.
*shudder* One can miss from that close?
When I was in Seoul three years ago to visit a friend, I was not impressed by the city. The people there were always in a hurry, and struck me as generally unfriendly. When you apologise for accidentally bumping into someone, your apology will usually be coldly ignored. There are also very strict social rules in place. E.g., on the trains, there are seats specially reserved for small children, elderly people, and the physically disabled. If you do not fall into any of these three categories, you are not allowed to take any of those seats, even when you are travelling during the off-peak hours and there are few other passengers. Of course, there are no laws in place to forbid you to do so, but you will be met with (silent) disapproval from the South Koreans. Or so my Korean friend warned me.
Another thing that struck me was the fact that the streets were strewn with litter everywhere. It was very unpleasant. How can one go about resolving this issue? After all, the lack of civic-mindedness is something that takes time to address, but you want clean streets now. Maybe you are thinking of making the act of littering legally punishable. That will certainly teach those litterbugs to be more considerate. So you pass a law saying that those who are caught littering will have to pay a fine.
This sounds like a good idea. After all, the advantage is that fining people for littering is a quick and easy way of filling up the governmental coffers, and so you instruct policemen to strategically station themselves in busy areas. But using manpower from the police forces to ensure public cleanliness seems like a colossal waste of all the specialised training all these policemen have received in preparation for their jobs.
What to do then? Maybe during the first two weeks after the ratification of the law, you delegate the assignment of catching litterbugs to a few policemen, to send the message that you mean business. After the fear of getting caught has been sufficiently instilled in the people, you surreptitiously transfer the policemen to resume their former responsibilities. You trust that there will be little littering now, because what matters is not the actual presence of the policemen, but the belief that those policemen are present, even when they are not.
But this might not work in the long run. People are not oblivious to their surroundings -- soon they'd realise that no one is actually enforcing the no-littering law, and they'd return to their old ways of leaving trash on the streets. So, periodically, you will have to make sure that there are policemen stationed in busy areas to deter littering. But over the long run, it would still lead to a huge waste of the police forces' resources and manpower. Besides, the policemen might not be so happy about having their other responsibilities interrupted just because they have to catch litterbugs. It is more important for them to catch thieves instead of fining people who throw away used napkins on the streets.
So what can you do? After all, you would really like to punish those litterbugs for their lack of civic-mindedness.
I would say that it is the wrong way of thinking about things. No doubt that littering shows a lack of civic-mindedness. But littering is also generally a small vice. My suggestion is perhaps rather unorthodox: Instead of punishing it, I suggest that we go out of our way to accommodate it. Accommodation does necessarily not mean that we have to continue living with the unpleasant effects of these small vices. Simply place so many rubbish bins on the streets of Seoul that there would be absolutely no reason for littering. Of course, there will probably be a few people who enjoy littering out of malice, but I believe that most people litter simply because they are too lazy to carry their trash with them if there are no rubbish bins within proximity.
Accommodate their laziness. By placing lots of rubbish bins along the streets, you are telling them, "I know that you are lazy, but instead of punishing you for it, guess what? I am going to make things easier for you!" Sure, you will have to spend quite a lot on money on the purchase of so many rubbish bins, but over the long run the benefits far outweigh the costs -- those who live in Seoul will get to enjoy a much cleaner living environment, and instead of hiring cleaners to work long shifts cleaning dirty streets, you can just hire them to empty and replace the trash bags, which takes a much shorter time.
Passing a law to punish litterbugs would also detract from people's ability to enjoy going out -- e.g., they would wonder whether to buy food from roadside stalls, because they would fear having nowhere to properly dispose of their trash, and at the same time they have no wish to carry the trash with them long periods of time. Placing lots of rubbish bins along the streets, on the other hand, makes it a lot easier for them to enjoy going out.
Our first reaction to vices is usually the desire to criticise or to penalise. Certain vices no doubt deserve such hostility. But it is important to pick your battles -- focus on combating certain vices, and give in to the rest. In fact, sometimes, going out of your way to accommodate a small vice would surprisingly end up making things better for everyone involved. This principle is useful in all aspects of life, and it is useful in both interpersonal relations and policy-making.
Decide for yourself what you can forgive and what you cannot. For big vices, it is important to ask, "What is right?" For small vices, it is perhaps more important to ask, "What works?"