Here i will give you some tips how to detect, Always ask for identification - you should ask for identification any time you are presented with the credit card. Now days many cardholders write on their card as ask for id in order to prevent the unauthorized use.
* he entire credit and debit card has some special characteristics that help both customer and merchant from frauds
* A hologram that changes color in the light
* A signature panel that resists erases and protects the cardholder's signature.
* A magnetic strip that transmit the specially coded information
* An embossed account number that is printed in the front is matched with the printed number at the back. I think it will be useful