Hide them so you don't use them

It's very tempting to spend money if you have it on you, it's even easy to spend credit cards.  They are "future" money not "real".  Many people convince themselves to believe that they will only use a credit card for emergencies, then soon after that these emergencies become everyday purchases.

The best place for a credit card is not in your wallet. Far too often spending on a credit card becomes easy and something that's not thought of until the bill comes and you have to pay the piper.  

I wrote about thinking before you purchase, this is even easier to do. 

Don't carry credit cards with you. If you need to make a purchase using a credit logo and not a debit logo then use your bank debit/credit card. It comes right out of money you already have in the bank to use and you don't need to worry about a bill at the end of the month. 

Put the cards in a safe place in your home. Always keep cash for your emergencies or even have a separate bank account that is there for emergencies.