When booking a guarantee book the category you will be comfortable with. If an upgrade happens then that's just icing on the cake; but don't expect it.
A travel wallet that can be put under clothing is a must. It's convenient and deters pickpockets. Just don't load it with everything you own. Then it stands out like a sore thumb.
Research is key: Know before you go.
Have an open mind and remember you aren't in America anymore. Learn about where you are going.
Don't sweat the little things.