1. How to use credit cards: First of all, you must understand the rules for using credit cards to avoid unnecessary losses. Secondly, you must understand the preferential policies of credit cards so that you can get more discounts when using your credit cards. Additionally, be aware of credit card interest and fees to avoid being charged unnecessary fees.

2. How to effectively use credit cards to get more discounts: First of all, you must master the preferential policies of credit cards so that you can get more discounts when using credit cards. Secondly, you should actively participate in credit card promotions to get more discounts. In addition, you should actively participate in credit card points activities to get more discounts. Finally, actively participate in credit card discounts to get more discounts.