Books

Knowledge is truly power. There is a lot one can learn from reading books. And although it's not really respectful to learn different styles when one is going to a school. It's always nice to know a little more then the average person, so I encourage you to please be respectful to your teacher and your school. To not be bound by one style is the smartest thing you'll ever do. I use Northern Mantis as my base system of fighting but I also study the Wing Chun style, Jeet Kune.