I didn't take step by step pictures of this one, but I'll give a little explanation. I cut our heart shape out of an empty cereal box so it had a bit of weight to it and painted it brown. You could also try heavy cardstock paper. (I might use brown cardstock paper and skip out on the painting part if I were going this route) I cut the eye holes out of the mask with a craft knife. The holes were about a 1 1/4" diameter circle. I actually used the base of a Children's Motrin Medicine cup to trace the circles. The center of my eye circles are 2 1/2" apart also. I hope that is helpful.
For the teeth, I used used my 2" heart punch and punched out a heart in white cardstock paper. We also cut ears cut out of brown paper, a black nose cut of black paper and toothpick whiskers (I cut the sharp edges off the toothpicks). If I had the flat, square toothpicks I would have used those instead of the round ones.
I punched holes on the sides of the eyes and used black yarn to measure my kids' head and then used it to secure the mask in place with knots.
And seriously...HOLY CUTENESS!!!
I have to mention that I originally wanted to glue a Jumbo Craft Stick to the back of the mask and have them just hold it up to their face. If you are doing this for a class, that is a route you might want to go! But since we've made masks before, my kids were insistent on having it sit over their eyes with the string.