1. Avoid shopping and banking on public computersLibrary computers can be a godsend if you need to pass the time or if your home computer goes on the fritz. But you should be careful about your online activities on these and other communal computers. Banking is a no-no, and shopping should be off-limits too. It is too easy to forget to log-out of accounts, and other users with more sinister motives may find ways to access sensitive data even if you do. The same goes for that free wifi offered at the coffee shop and the local McDonalds. Unsecured, public networks are convenient for browsing the web and laughing at the latest memes, but they are not the place to be entering your MasterCard, Visa or Discover numbers.
2. Look for secure sitesEven when you are on your home computer or a secured network, be aware of where you are entering your credit card information. Generally, sites for large retailers such as Best Buy or Sears will have sufficient security to protect your credit card information. A no-name electronics store with a Russian web address? Maybe not so much. Even if a site says it's secure, don't simply take its word. Look for addresses that start with 'http s' and a padlock. If you are shopping on a new site, double check its privacy and security policies too.
3. Protect your credit card in publicIf you are shopping old-school (that would be in a store), you still need to protect your credit card number. Don't leave your card lying out on the counter where others may be able to see and memorize your numbers.
Also, while most clerks are honest, keep an eye on your card as it is swiped. There have been reports of some instances in which a clerk will swipe a card twice - once on the store register and once on a separate skimmer they use to collect numbers for their own devious purposes.