Yahoo Finance and Creditcards.com have a story on how bad your credit mistakes are. Here is their list of how bad things are on a scale of 1 to 10:
1. Using a card in a pinch: 2
2. Paying the minimum: 4
3. Balance transferring: 5
4. Too many cards: 6
5. Paying late: this is a 6
6. Maxing out a card: 7
7. Cash advance: 8
8. Missing a payment: 9
9. Debt settlement: 9.5.
The one thing missing from their list: cancelling your old cards with no balance. This is a 7.5. One of the big factors in your credit score is the length of time you have had credit. If you cancel an old card, this will have a negative effect on your credit.
Read the whole article for more from Creditcards.com on how to be responsible with your credit.