My method is a bit different than jay12345's. We offer full service quick printing. We also offer self service copiers in the front of our building. Whenever someone comes in, and they look like they are going to use the self service machines, I always greet them and to let me know if they have any questions. If they do, I explain the basics of the machine to them real quick, even in the are only getting a single copy ($0.05). This will HOPEFULLY in the end catch up and we'll have a good number of people that know how to use a simple copier. Of course I am spending a little bit of time on those small customers, but it should work out better in the end.
In regards to artwork, we have decided to turn out art department into a money maker and it has worked out AMAZING. We are constantly 2-5 days out for proofs and our designers are turning out profits for the company along with good design and layout. If you send me a crap file and expect me to fix it, you will incur our $20 layout minimum. Only 1% of my customers have an issue with this and they are usually a pain in the ass to work with so we figure out a way to charge them extra over time. Don't let the customers and their lack of experience wear you down. Educate them or do the work (charge them) and they will appreciate you more!