On escalators, stand on the right, pass on the left. Just like on the autobahn or freeway. In lands were it is the opposite, do the opposite.
You have to ask for the bill in a restaurant, it will never be given to you until you ask.
Roll your clothing, you will get more in your suitcase.
Take photos of pages from a guide book. Then you don't have to destroy it or bring it along.
Use a translation app, like "google translate" for menus, signs, and even gravestones.
Join FB pages for the cities you are visiting to find out local festivals, events or even to get restaurant tips.
Use YouTube for navigation help in stations and airports.
I got the "Europe on $5 a Day" guide book when I was 17 and hoping to back pack around Europe with a friend. She backed out and my parents wouldn't let me go. Wish I still had it, for some comic relief.