Thieves may attach skimming devices to the exterior of an ATM or point-of-sale terminals requiring a PIN, or personal identification number. It's worth the few seconds it takes to glance before you swipe.

"Always take a look at the machine to see if there (are) any visible traces of activity, such as glue or scuff marks or loose bits around the PIN pad or the place where you insert your card," says Manisha Thakor, co-author of "On My Own Two Feet: A Modern Girl's Guide to Personal Finance." "Those are telltale signs that an attempt may have been made to attach a skimmer."

She says you should pay close attention when you're visiting an ATM in a low-traffic locale, where it's easier for someone to attach a device. When in doubt, use a different ATM.