Keep all credit cards, cash, and Travelers Checks in a money belt.
Travel safely. Like anywhere else, crimes do occur in the United States. Use common sense: do not walk alone at night, be aware of your surroundings, and do not be afraid to ask people about a particular area if you are unsure of its safety.
Do not hitchhike.
Do not leave valuables unattended at any time (even in a rental car).
Be sure that all your luggage is locked (using a TSA-approved lock, if you will be flying).
Carry a United States identification card (student ID, health insurance card, driver's license) at all times.
It is also a good idea to carry a U.S. contact telephone number in case of an emergency. For police or medical emergency assistance anywhere in the United States, dial 911 from any telephone.