Whenever you get a creditcard bill, don't wait for the last date to pay the bill. Pay the minimum amount immediately and after some time if you get more money you can pay later. Usually people want to pay the maximum and they wait for the money but sometimes it may become late to get and meanwhile the last date will be passed. If you don't have minimum amount with you to pay, put a reminder to remind everyday with the last date to pay the creditcard bill so that you won't forget when the last date is.
Better write down the statement date and last date for every creditcard you have.
My strong suggestion is not to use more then one creditcard.