Welllllll, I haven't done any FY costumes yet, but their overall style is pretty much in line with what I like to do.
(If that makes any sense.) So if you want to ask some specific questions about how you'd go about planning it, what to use, etc., I'll try to help you out.
I also make them, but my favorite part is figuring out how to translate 2D to 3D without spending unlimited money.
Oh, and if you haven't looked at Cosplay Closet's Tips yet - http://www.cosplaycloset.com/TIP/TIPframe.html
- I'd recommend that immediately.