4. Never, Ever Miss a Payment Deadline
One of the cardinal rules of intelligent credit card use is to pay on time, every time. Though a lot of people intend to pay off their credit cards on time, many just forget.
Missing your deadline by a couple of days might not seem like that much of a big deal to you, but credit companies will be very quick to levy late fees and even possibly increase your APR%, especially if you have been late on more than one occasion.
If you have many credit cards and have a hard time keeping track of all the deadlines, it makes a lot of sense to keep a monthly alarm on your phone or calendar for each of your credit card deadlines, to make sure that you are never late.