That means, for instance, every time you charge $100 on your credit card, make sure you put $100 in your savings account.
And here's an easy way to do it:
Make sure you have signed up for online banking for your checking account.
Make sure you have a savings account linked to your checking account.
Every time you use your credit card, transfer money from your checking account to your savings account.
You'll be earning interest, and you'll always have money set aside for your credit card bill.