8. Make "first-time" cases work in your favor
If you've never been late before or you've never had an over-the limit fee assessed, ask directly for a removal of a late fee or over-the-limit charge. A little-known fact is that most credit card companies give their employees the authority (without even getting a supervisor's approval) of waiving late fees once every 12 months. If this is the case for you, do ask to get those fees removed. You might be surprised at how easily they will agree.
9. Mention their competition
When you're negotiating for a lower interest rate, mention that you might be inclined to take your business elsewhere. The point here is not to make an idle threat. And I wouldn't start the conversation off with talk about you possibly going to a competitor. But you'd certainly be justified in exploring your options — and telling the creditor about other companies' balance transfer deals or lower interest-rate offers — if they won't budge on high interest rate cards.
10. Document all conversations in writing
In the event you have to go back and get something corrected, or removed, it helps your case if you can refer to your written notes and say, "I spoke to John Smith on this date, and was told such and such."
If all these efforts fail, you can always ask for a review of your account again in a few months. For example, if your request for a lower rate is denied, ask a supervisor if he or she would be willing to reconsider their position in, say, three or six months. If they agree, document the person's name, and put a reminder on your calendar to call back at the appropriate time.