Materials: cardboard, duct tape/hot glue, scissors, measuring tape, Xacto knife, pen/pencil, pull chain, paint (optional).
Step 1: Measure and Cut Hat
Measure the circumference of your head, add a couple of inches, and use the measurement as the length of the rectangle of cardboard you use. The width is how high you want the hat to be. Mark the cardboard with these dimensions and cut the piece out.
Step 2: Score the Cardboard
With the Xacto knife (or similar tool), score lines down the cardboard. Score all the way across the cardboard so that it wraps around your head.
Step 3: Tape the Hat
Now tape the ends of the cardboard to each other to form a cylinder. Make sure that it is the correct size for your head.
Step 4: Top of the Hat
Place the cylinder on another piece of cardboard and trace around the base of it. Then cut the circle out of the cardboard. Then attach the circle to the top of the cylinder with duct tape or hot glue.
Step 5: Make the Brim
Now trace the base of the hat again on a piece of cardboard. Determine how wide you want the brim to be, and measure that width as the distance from outside the traced circle. Then cut both circles. Turn the hat upside down and place the brim on it. Attach the brim using either duct tape or hot glue. You have now made the hat, and you can paint it if you want.
Step 6: Make the Monocle
Measure the diameter of your eyeball. Use this to find out the circumference of the center hole of the monocle. Mark a circle of the correct circumference on the cardboard. Then measure about a half-inch distance from the circle you have drawn and draw another circle to form the monocle. Then cut both circles out. The monocle can now be painted or colored.
Step 7: Attach Chain and Wear Monocle
To attach the chain to the monocle, just duct tape or hot glue it to the back of the monocle. To wear the monocle, attach a couple of pieces of double-sided tape to the back of it and put it over your eye.