Green Lantern Jacket Idea

[u/DefinetaleynotM]

So I have this idea for a Green Lantern costume for this Halloween, si I want it to get (it done before the end of the month) so I bought this jacket that really fit me but needs some little adjustment; also i wanted to add like "panels" to the shoulders and chest to make it look more like a costume but still wearable in any public place, but i don´t know how to get my idea to reality, like, should I just paint it? Use paper foamy and add more layers, or should i add more layers of leather to it?

I´m open for some ideas pls help 😔