This is the second cowboy hat I've made out of duct tape
Step 2: The brim
Step 3: The brim pt. 2
Step 4: Sides of the hat
Step 5: Top of the hat
Step 6: Assembly of the sides and top
Step 7: Adjustments and dimples
This is also the time to adjust the shape of the hat, once again this process is kind of hard to explain, but it should suffice to say that some trimming and re-taping is necessary. Feel free to ask questions in the comments.