The credit card you carry around in your pocket, may not work as well when you travel overseas. American credit cards are antiquated and still use magnetic strip exchange to transfer information. However, in Europe, and many other countries, they use chip-and-pin card technology. But this can be a problem at automated kiosks and small shops.
Two options include bringing cash with you in the currency of the country you are visiting. This will help you to use your card less. Another option is to try and get an American credit card with an embedded chip. There are not many choices, but there are some out there. J.P. Morgan offers a Select Visa and the British Airways Visa has the chip technology. Also, Diners Club is upgrading its customers with chip-enabled credit cards. Wells Fargo is to begin a pilot program with the new style cards, but it has yet to start.
If neither of those options works, try getting an AAA or Travelex prepaid debit card with the chip-embedded technology. The exchange rate will be higher, but will allow you to pay without any issues.