To maximize space in a traditional medicine cabinet, line the inside back of the cabinet and door with sheet metal, then use magnetic containers and hooks to hold supplies. Great way to get rid of "loose" items floating around your medicine cabinet!
Best Emergency Notebook I've seen with printables so you can make your own for your family! The military teaches you how to do this. It's called "my life in a box" for emergencies. "It's my life in a box.