Make sure you have a signed, valid passport and visa, if required. Also, before you go, fill in the emergency information page of your passport!

Read the Consular Information Sheets (and Public Announcements or Travel Warnings, if applicable) for the countries you plan to visit. 

Leave copies of your itinerary, passport data page and visas with family or friends at home, so that you can be contacted in case of an emergency. 

Make sure you have insurance, which will cover your emergency medical needs, while you are overseas.

Familiarize yourself with local laws and customs of the countries to which you are traveling. Remember, while in a foreign country, you are subject to its laws!

Do not leave your luggage unattended in public areas and never accept packages from strangers.

While abroad, avoid using illicit drugs or drinking excessive amounts of alcoholic beverages, and associating with people who do. 

Do not become a target for thieves by wearing conspicuous clothing and expensive jewelry and do not carry excessive amounts of cash or unnecessary credit cards.

Deal only with authorized agents when you exchange money or purchase art or antiques in order to avoid violating local laws.

When overseas, avoid demonstrations and other situations that may become unruly or where anti-American sentiments may be expressed.