Remember to contact your credit card company to let them know you will be making purchases and using that card outside your normal location. This is especially true if traveling outside the US.
Look for transaction fees. Many credit card companies charge foreign transaction fees that can be around 3%. You can check out www.bestcredit.net to compare cards and companies.
Always have a back up card. Or, if traveling with a spouse or significant other…each take a different card with you.