I worked from a reference drawn by Thores Shibamoto for one of the Trinity Blood light novels. It provides less source material for the construction process, but this particular design is less-cosplayed and therefore more unique.
For interests' sake, here's my main reference:
It's one of my favourite images from the entire series!
I started construction in June of this year, right before spending a month working out in the boondocks at a Girl Scout Camp. It was my Camp Project.
The first piece constructed was the breasplate. I had never made armor before, but luckily I was able to borrow some techniques from Shushuwafflez on DeviantART. What I ended up doing was gluing together three layers of craftfoam to create a sturdy base, then I smoothed out the edges using bias tape. The small designs were made by injecting hot glue into fondant molds. I discovered that is extremely frustrating to prevent bubbles from forming in the hot glue as it is injected. Fortunately the only casualties of this process were a few pieces of craft foam and some hot glue shapes that were fatally wounded by bubbles.
After my fingers had sufficiently recovered for a or week two (hot glue guns make for sore hands!) I made Seth's upper arm armor. The process was very similar to the breastplate, only this this I would be using only a single layer of craft foam. This became a bit of a casualty later because the craft foam needs to curve a lot to fit around my arm. I used brass brads to attach these pieces to the sleeves of my bodice. This makes my armor 100% removable so I can store the bodice folded without risking damage to the rigid pieces.
One of the largest pieces of armor was actually part of my hat. It's the piece that fits over the front of Seth's head to hold the hat in place. What I imagined and what I could actually make using my supplies were, unfortunately, two completely different things. The finished piece does not fit over my head as far as I would like. Fortunately there were no casualties at this stage, except for a few more hot glue shapes.
Final pieces of armor were part of my shoes. I purchased pointe shoes specifically for the stiff toe that would be able to support craft foam armor. One note: hot glue works EXTREMELY well on pointe shoes. Those damn armor pieces are NEVER coming off...
I used hot glue shapes in a few other places on the costume, hot glued directly to the fabric. The hat and skirt each have accents. In retrospect I wish I had used hot glue shapes on the train, however my fingers are probably happy not to have been used to make all those extra hot glue shapes!
Finally everything was spray painted gold. Out of three shades of spray paint I tried out, Krylon's Bright Gold looked the most realistic. Funny story! Due to TSA rules I wasn't able to carry my cans of spray paint with me when I flew back to New York for college. This instigated quite a search for more Krylon because the local hardware store does not carry the Krylon line. Odd, yes. I am forever grateful that my costume design professor was able to pick me up a can on one of her trips to Wal Mart.
I've had a few problems with spray paint rubbing off, but otherwise this process was an extremely good one. A bit of orange craft foam is showing through around the edges of my shoe armor, but due to the way I walk where my shoes sometimes scuff together, it is unlikely that I will be able to fix this completely.