With all due respect to Robert Fulghum, you can learn a lot more outside of the classroom than you can in it.
Here are some of the things I learned from traveling around the world for four years:
Be patient. You will experience flight delays, screwed up food orders and lost hotel reservations. Take it in stride.
Live simply. Everything you need you can carry in one bag, maybe two. You have no idea how useless most of the stuff you own is until you are forced to go without it.
Always take time to recharge your batteries. This isn't some sort of alliterative way of saying you should take time to rest. I literally mean you should make sure to keep the batteries in your devices charged. Resting is good too, however.
The best things are not always the most expensive things. You can often have a better experience eating street food or staying in a hostel than you can at a five star restaurant or hotel.
Take the wisdom of others who have gone before you. You will meet travelers who have been where you are going. Listen to them and take their advice
Don't make a scene. Travelers who get a bad reputation are the ones who are loud and cause a fuss. Keep to yourself, lower your voice and it will solve many problems.
Try it, you just might like it. You don't know what you like until you try it. If you don't like it, you never have to try it again.
Wash your hands. This is especially after using a squat toilet. Doubly true if there is no toilet paper.
Eat lots of fruit. Try to eat fruit every chance you get. It is good and good for you.
A stranger is just a friend you haven't met yet. This old adage is actually true.
Take time to observe. There is more you can learn from sitting at a cafe or pub than you can from a reading a book. The little things are often important.
Walk in the shoes of others. If you think a place is exotic and foreign, just imagine what they think of you.
Saying "hello" in another person's language can go a long way. Taking the time to learn a few words of another language can sometimes do more than having a full conversation in your own.Don't be afraid to haggle. If you don't stick up for yourself, no one else will. Asking for a better price might actually increase the respect people have for you.