M = Memory. Never rely on just your own memory. Back up with research. (It will also widen what you can write about. Write about what you know is good advice but add to that the thought about expanding what you know and your range increases!).
N = Notebooks. No writer can have too many of these. I use mine to brainstorm ideas. I also had some notebooks made up with the front cover of From Light to Dark and Back Again on them and used them as prizes in my cyberlaunch. Did not cost too much. Went down very well.