I know this is an old post, but if its any help--Robo-Ky is also my favorite GG character, and I have tried (and failed) at cosplaying him before in 2007.
I have heard from other successful Robo-Ky cosplayers that LEDs right under the eye slots make the eyes on the mask glow. As for making it shiny and metallic, there are several different approaches. I used papier mache --it was ok. I think most might suggest wonderflex or worbla, and a badass paint job.
For high quality clothing...Personally, I like high quality fabrics, like low luster satins, but I think many use high quality cotton for the low price. Its best to use a pattern of some sort, some can be obtained on the internet, or you might want to modify a men's trench coat pattern purchasable at a fabric store. The belt can be made simply with fabric, purchasable belt buckles, and foam/worbla. I might recommend craft foam so that you might be able to etch out "Ennui" in the buckle.
As for overall advice, I would recommend separating the elements of the outfit and working on them individually. There's a lot of belts and buckles and small details. It can be overwhelming, but, if you have determination and patience, it will be rewarding. ^^ Don't fret if you make mistakes, its part of the learning process. What you don't accomplish right this time, you know what to do better next time.
~The flying toasters of Microsoft are baking Apples in the After Dark~
Celebrating 12 years of cosplay
-Millia Rage (GGXRD) -Metagross gijinka (pokemon)
Lineup: ALA 16- PMX 16- AX 16- Anime California 16 -Wondercon 16
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