I will share travel tips from time-to-time (usually in lots of 10). Someone might as well benefit from my experiences, observations and goofs. Thankfully, some of these tips (including the first one) I learned from others' mistakes.
1. Don't lock your bags when flying (unless you have security-friendly locks). Security people will just break any other locks so they can peer into your bag. They usually leave a note to say they peeked, and my bag has been very popular. So much for the claim that they make random checks! I was checked at every USA leg.
2. American and Iberian Airlines do not serve food. Plan ahead. In other words, eat before you go or bring food.
3. Post offices can be very hard to find. I still have a mitt-full of postcards to send and no stamps in sight.
4. Good postcards can be a little to a lot cheaper when they are bought AWAY from the tourist centres.
5. Most libraries have free internet. Sometimes it's available in 15 minutes blocks only.
6. Don't stop smoking just before going to Spain. The whole country smells like smoke. The restaurants even have signs posted -- saying you CAN smoke inside.
7. You can still find lots of wonderful non-fast food in the USA. You just have to look.
8. A cable-car ride should be compulsory in San Francisco, and so should a visit to Alcatraz.
9. Watch out for bike paths in some European cities. Bikes are serious business in flat places. If someone rings their bike bell at you once or twice, you are probably on THEIR turf, so move aside.
10. Wherever you are, be sure to take a tour through a supermarket or two. You'll learn heaps more about the local preferences, food and culture.