Managing your credit cards isn’t a one-and-done task — you’ll need to keep at it to get the most out of your plastic. Every month, the Nerds round up a new set of tips to help you maximize rewards and minimize costs with every swipe. For August 2015: 1. Use bonus malls to cash in on back-to-school shopping. If you or your children are starting a new semester in August, you probably have some shopping to do.