Borders vary greatly from continent to continent. In the Middle East it may take you several hours, getting your passport checked half a dozen times, to cross from one country to the other. On the flip-side, crossing some European borders is such a non-event that you won't even know it happened. All borders, no matter how relaxed or strict, deserve your respect.
All international travelers are required to have a passport. If you don't
have one you will have to get one. In addition some countries require
that you have a Visa before entering their country. You will also want
to check into getting an International Health Certificate (also known
as the "Yellow Card"), and you will want to check that your
Insurance covers you while you are overseas.
Passports - Visas - International Certificate of Vaccination - International Drivers License - Travel Discount Cards
The ability to speak even a little bit of a foreign language will add to the enjoyment of your trip, demonstrates your respect and shows your willingness to reach out and make an effort. Nonverbal communication is a very powerful medium when traveling primarily because it makes for an easy replacement for speaking. And simple gestures are a large part of this form of communication. Gestures vary greatly from country to country, and can easily be the source of slight misunderstanding or serious offences.