The same way that you would do for Fiberglas (that is, incidentally, a trademarked name). It's also the way that I make my Hallowe'en facial appliances (as you can see in my avatar). You make a positive of what you want to duplicate. In my case, that's plasticene that I sculpt onto a Styrofoam head; for you, that might be taking an original hood or whatever. Coat it liberally with mould-release compound or at least WD-40. I use paste wax, but that's just a habit from the old days. You then lay down a few layers of Fiberglas or similar substance on top of that to make a negative mould. Once that has dried, you put down your carbon fibre the same way that you would with glass—matt, resin, squeegie, matt... etc. until you have a piece that is as thick as needed. (And you don't need a lot of that ****; it's incredibly strong.) For total accuracy, you then enclose the whole affair in an air-tight garbage bag (or similar). Hook the intake side of a compressor into a hose that connects to the bag, and just vent the exhaust as usual. After that, just cut off the trim, maybe give it a wax coat if you're not going to paint it, and send it on it's way.