I made these a while ago when I used to wear hats on a regular basis. I had a similar hat in black that was a little small for me and made a pattern for a new one for me after studying it one day.
It's a little hard to tell on the picture but the fleece has polar bears on it. The smaller of the two hats is being sported by my bear Tay so you can tell what it looks like on.
Tutorial - Parts needed (Note I don't use measurements at all for this pattern)
Each piece A is one eighth of a circle. The larger you make the circle the ploofier the hat.
Piece B is made of card (or anything else you want to use as stiffening for the peak.) and part D should be large enough to cover piece B after it is folded once.
Piece C should be as long as the width of your head. The width depends on how much of a lip you want to give the hat.
Step 1: Make sure to cut piece C so that it stretches along the length. That way you can make it a little smaller than head width and the stretch will ensure the hat does not fall off. Sew the short end together.
Step 2: Sew each of the eight piece A sections together to make a circle. It's turn into a sort of bowl once put together completely.
Step 3: Sew piece C to the small opening that occurs of the circle. Make sure the join from step 1 aligns to one of the joins on the circle.
Step 4: This is the trickiest part of my pattern.
Fold piece D and tuck piece B into it as shown by the image on the left. Pull the material so that is is fluch against the peak like the image on the right. Sew along the bottom edge and cut off the excess just enough that you have enough to allow you to attach it to the rim of the hat opposite the join made by piece C (It isn't the prettiest of attachments but you can't see it when you wear the hat so it's all good
Step 5: Cover a rounded button with a bit of scrap fleece and attach to top of hat.
And done. If you skip step 4 entirely you end up with a beret. Good luck