1. Sign all your credit cards on the signature strip immediately as you get them.
2. The pin numbers -- they are the key to your credit card, if you can't memorize them, write them on a paper and keep them at a safe place. Don't write them in every nook and corner of your office, workplace or home. If anyone gets the pin of your credit card things will get serious for you.
3. Don't carry a wallet full of credit cards with you.
The last thing you would like is dropping a credit card from your wallet, simply because it was too unmanageable.
4. It is a good habit to keep the credit cards separately from any identity proof like drivers license in your wallet. The reason is that if someones gets your wallet he shouldn't get complete clue about your identity.
5. People often leave their credit card unattended, where they become easy prey for fraudsters. It is always advised to keep them safely.
6. During any credit card transaction, don't let the credit card stay away from your attention. Get it back as soon as the transaction is completed. Keep a check on what the counter clerk is doing with your credit card. The reciepts of any credit card transactions should be kept safely and if they are not useful it is good to destroy them.
7. During online transaction using credit cards make sure that the website is SSL protected and shows the secure transaction signs.