Step 1: Tools and materials:
-"metallic gold" Fimo clay (x3)
-black, brown and light orange chalk pastels
-clear nail polish*
-a rolling pin
-hot glue gun
-a big blue strass
-a circular pastry cutter
*(or "Fimo gloss varnish" but you may need a specific brush and the result is just plain messy)
-plastic wrap & duct tape (to protect your desk)
I printed GnatGoSplat's texture from http://nene.modthesims.info/download.php?t=328344 to respect the proportions of the crown...
Step 2: Lets get strated!
(also protect your tools with a plastic wrap before cutting the clay)
Slightly crush the clay, then place the logs from large to small.
Crush the chalk pastels into powder, then apply heavily a dark brown colour on the smallest logs with a medium size make-up brush and progressively darken the edges with black pastel powder...
Step 3: Sculpting the front part
Don't hesitate to smooth the edges with your fingers to give the crown an "authentic" look.
(Use some hair spray as fixative so the pigments last longer.)
Step 4: How to sculpt the leaves:
Flatten the clay with the rolling pin and cut it into a tear-drop shape.
Pinch the corner of the leaf as shown in the picture.
Carve two thin lines in the middle with a toothpick, then use the end of makeup brush handle to sculpt the leaf.
Apply a light orange pastel powder on the lines and use a rusty brown colour to darken the carved areas & edges.
Step 5: Finishing the front part
Glue the leaves together with some liquid fimo (or nail polish) and sever their edges.
The liquid Fimo stays very flexible once baked, so you won't have any problems to adapt the crown to your forehead.