Before leaving the country:
Contact your bank and put a travel notice on your account; provide the location(s) you'll be visiting and dates of your trip. Be sure to inquire about any fees or restrictions you might encounter when using your bank card abroad.
Research ATMs locations and networks. ATM member networks may be indicated on the back of your card; otherwise contact your financial institution to inquire about ATMs that you can use and any fees that you might incur.
Credit Cards by Sean MacEntee -- Some rights reserved
Have a back-up plan (such as another card or traveler's checks) just in case your card does not work.
Find out if you have any daily limits on your bank account or credit card.

Image courtesy of "Images_of_Money" Flikr Creative Commons