Wear a condom.
Stay away from Songtan Sally.
DON'T develop feelings for a juicy. In fact, don't even buy them a drink.
Contrary to popular belief, the girls off base are "cleaner" than girls on base.
Don't break curfew or you'll be sorry.
Drink with people you trust. If you have a tendency to do stupid things when you drink, don't drink at all. It's ridiculously easy to lose stripes over there.
MUST DO: Tour the DMZ if you get the chance.
There is a ton of stuff to do over there. Make the most of it.
Oh, and wear a condom.