The materials are simple:
cardboard (I will discuss types below)
X-acto blade (or laser cutter)
paper (to print the pattern to)
elastic band (or more cardboard, discussed below)
Any cardboard will work, but it won't look very good unless you find a sheet without bends in it. So you at least want to find pieces of cardboard that are new-ish. Obviously, the stiffer stuff will work best. My personal favorite type of cardboard-esque material is old board game boards. Don't destroy a game just for one, but occasionally you can find old ones in the trash. I had an old risk board that I had been looking to re-purpose since the rest of the game was gone, this was a perfect use. Board game boards are thin, strong, stiff, coated, and dont bend or crease easily. Perfect candidates :)
You need something to wrap around your cranium to keep this mask on. I like to use that soft elastic band or fabric that you can buy at any fabric / craft store. If you don't feel like buying anything, you can always just use a strip of cardboard fitted to your cranium-size.
Edit: instead of an elastic band, I used a piece of scrap cloth fabric and cut a ribbon of it out. This way I can affix part of it to the mask and then just tie off the rest behind my head.