Pay yourself first. Put even a little amount in savings.
Pay your bills. Late payments show up on your credit report.
Don't use your credit card if you couldn't pay it off this payday. If you don't have the extra money this month, you won't have it next month either.
At the end of the pay period, if you still have money in your checking account, move it to savings and start fresh with your new paycheck. It's an easy way to save - even a little bit.