Once all your moving snakes are added, you can add non-moving lighted snakes using the other 6 light-pipe holes. It's helpful to sew the tubular crin to the wig so it stays in place and the light pipe doesn't pull free.
Add more non-lighted crin, rubber snakes, fishing lure worms or other details to fill out the headdress. You can sew the snakes down in a pattern or let them swing free.
To keep it on my head, I used contact cement to glue a few wig clips into the inside of the headdress.
My hair is blonde, so the dred lock wig didn't fully cover it. I ended up adding a second green and black wig underneath the headdress and clipping the headdress to that wig, then clipping that wig to my head. This actually worked really well! The headdress stays balanced as long as I'm fairly careful with my movements.
I sketched a few different ideas for the rest of the costume, with lots of inspiration from Pinterest. I decided on a corset and skirt look. I got the corset from CorsetStory and decided to recycle a skirt I had from last year's Witch costume.
I added some extra tubular crin and some fun scale patterned fabric to the corset with E6000 glue, and found a perfect reptile-patterned long sleeved mesh top at Target for cheap.
I finished off the look with my Eye of Newt necklace -- always a huge hit.