This is a method commonly used by cosplay costumers. Most of my research brought me to Amethyst Angel's tutorials, which go into greater detail for more specific and complex prop builds. Here I simply cover some of the basics of this technique.
Step 1: Getting Started
Hot glue gun
Styrene Sheets - Most people recommend .20" thickness for flexibility and ease to work with. Smaller panels can be found at
hobby stores, but for larger sheets you will have to shop online.
Acrylic paint - Gold, Silver and Black (or any other colors you want to include). Black is used for weathering.
Paper - to plan out your cuts
I started by planning out the crown's design on paper, to make sure everything was symmetrical and fit together nicely. Since I was using smaller styrene panels which I found at a hobby shop, my design was made in several smaller pieces that would be assembled in a repeating pattern.
When I was happy with the shape of things I traced the design onto the styrene sheets and cut them out. When everything was assembled, it looked pretty decent. At this point the crown could be bent into a ring with the flexibility of the plastic. It still looked somewhat odd and flat, so I decided to try a little shaping.