To make the brim I follow a tutorial created by Threadbanger and found here
. Because their tutorial is so great I won't go into too much detail here, but basically I traced the brim of another hat onto some construction paper (which gives a nice flexible brim). To get the depth of the brim I measured my other hat which was a little over 1.5" and freehand drew the inside shape. I then folded the paper at the midpoint and cut it to ensure both sides are the same.
After cutting out the shape I covered both sides in duct tape and then traced out and cut two pieces of fabric 1/2" larger than the brim. When cutting out the fabric make sure to cut straight across the back edge (don't follow the inner curvature of the brim pattern).
Pin and sew the two pieces of fabric together along the curved front edge and flip it around so the stitches are inside of what is now a pocket.
Place the paper brim inside the pocket and pin and sew along the back curve of the brim making sure that the fabric is pulled tight from front to back before pinning.