Usually it is a waiter, waitress, or sales clerk that will be the one to try and copy your credit card information. Most merchants have enough sense not to sh*t where they eat. Employees tend to be more transitional.
Something that I do is I remove the three digit security code from the back of the credit and debit cards that I carry on my person. I do this by scratching off the numbers then blacking them out with a sharpie.
That will not prevent all credit card crime. But it makes it much more difficult for thieves to order merchandise online. Also when I travel I will use a different credit card than the one that I usually carry. That way only charges that I make on my trip will be on that statement. I also save every receipt and keep track of how much money I've spent.
If you scratch the three digit number off the back of your credit cards and you have a bad memory. You can store that number somewhere in your cell phone as part of a bogus phone number.