Grab a party hat, cut out felt and head to the glue gun. In the middle, put some glue for the party hat to attach too. When attaching the party hat, make sure it's the front smooth part of the party hat. This will help the seams of the party hat to aline with the felt side edges. When putting the party hat down on the glue, start with the lining up the top of the hat to the felt and work your way to the bottom.
Once the hat is attached to the felt, start hot glueing the rest of the felt around the hat.
Where the felt overlaps on the party hat, glue the seam down so everything is secure.
Any excess felt on the bottom of the party hat, cut off.
Take your glue gun and place in between the party hat and felt. Add glue around where needed. If needed, pinch the bottom of the party hat and felt where just glued with finger tips to secure it all. Be careful to not burn fingers.