You will need:
A piece of fleece. (about 1' X 2')
A tape measure.
A sewing machine, or needle and thread.
You can use leftover fleece from another project, or cut up an old sweatshirt or blanket, or buy a cute piece in the remnants section.
Step 1: Measure the Head.
Then measure about how tall the hat should be, from the eyebrows, to the top of the head.
For my hat I have a head circumference of about 22" and a height of about 7"
Step 2: Cut the Fleece
The length of the fleece should be about three (or four) times the height of the hat. In my case 3x7" = 21".
It's okay to make the length longer. It will give you more fabric to make into the cuff of the hat. You can always trim it, to make the hat shorter, but you can't make it longer.
Now fold the hat in half, right sides together, and get ready to sew.
Step 3: Sew the Hat.
Now trim your threads, and turn the hat right side out. Roll up the bottom for the cuff. (mine was a little too short, so I could roll the cuff only once. )
Step 4: Embellish
I sewed on a patch to spruce it up. You could sew on ribbon, or buttons, or whatever you can think of. You could even just draw on it with a sharpie.