Things you'll need:
Foam hat shape
Exacto knife
T-pins
Felt
Ribbon
Paper
Pencil
White glue
Plastic Wrap
Step one: Find a Styrofoam object that approximates the head size of your squirrel and creates a nice dome shape for your hat. This will be used as your hat block. In my case I had an old easter egg lying around. If necessary carefully cut and shape the Styrofoam to create the dome shape you are looking for.
Step two: Wrap your hat block in plastic wrap. Don't skip this step no matter how much you think that the tiny glass balls on your easter egg should keep the glue and hat from sticking to the block.
Step three: Wet your felt with warm/hottish water. Squeeze out excess water. Stretch the felt over your hat block securing the felt with T-Pins as you go. (if you are using something spherical make sure to not go past the equator of the hat block because getting the felt off will be a disaster if you do) Soak your felt in white glue. If you care to you may add a second layer of felt but most squirrels I know are fine with less then perfect craftsmanship in their chapeau. Leave to dry overnight.
Step three B: Cut two squares of felt that each will fit two bits of brim. Use a generous amount of glue (ie, soak) to glue the two pieces together. Squish them together for a bit and leave to dry overnight.Step four: Now that your dome is nice and dry and stiff it should (if you managed to use plastic wrap) release easily from the hat block once you remove the pins. (if you did not use plastic wrap you will have to carefully cut the hat block out from felt piece by piece.) Carefully cut off the excess felt that is not to be part of your hat dome.
Step five: Place your bare dome on a piece of paper and sketch around it the ear flaps and brims you will require. Use this time to adjust dimensions as needed. Cut out the ear flaps pattern making sure to leave extra length at the end so that you can flip a bit of it into the inside of the hat. Cut out the brims in big D shapes (as opposed to C shapes). You'll need the extra to attach the brim and for mistake wiggle room. Tape the patterns to your dome to make sure that they work well.
Step six: Cut out the ear flaps from felt. Attach bits of ribbon to the end. You may need to use glue to reinforce the felt at the ends that are being sewn. (If you hate sewing that's cool. Just use gel superglue to attach.) Attach the flaps to the dome with glue and a few quick stitches. Once attached and the glue is dry carefully tie the ear flaps up with the ribbons.
Step seven: Use the double felt piece that you made in step three. Cut out the D shapes for the brims. Place the dome with ear flaps over the brim bits and mark with a pin where the center on the brim should be. I then made a quick pattern of the curve that the hat dome makes to get a nice match. Use your quick dome curve pattern to determine where the brim will end and attach to the hat. Cut through only one layer of the felt and remove. Leave the other layer intact but cut a few slits in it so it will easily flip into the dome of the hat for attachment.(this bit is important as it gives you a nice finished look) Attach with white glue. You may want to replace the hat onto your hat block so that the brim attaches firmly. Repeat for the second brim. (You may need to reglue bits of the top brim back on.)Step eight: TADAA! You're done! Unless you're feeling like a perfectionist and want to line the hat on the inside so you can't see all the attachment points. Honestly though it's for a taxidermy squirrel. Fuck it.
Update: And now for your viewing pleasure. In all his ::cough cough:: natural glory. Squirellock Holmes.
