dont make your own yet, i use this
http://img168.imageshack.us/i/carbonfiber.jpg/ has worked perfectly everytime i use it.
heres my lil tutorial for you
First you select the area your working on,
copy and paste that as a new layer, desaturate it and play with the brightness/contrast to get it dark like this
open the carbon donor and cut a big enough chunk to cover the part your making carbon (obviously might have to make the carbon a bit bigger but dont cut a tiny tiny chunk out if you know what i mean lol) maybe lower the opacity to make sure everythings covered
right, now it gets a bit harder, bring the carbon back up to 100% opacity, hold ctrl and click the thumbnail of the body part in the layers box, you should have the crawling ants around the wing like pictured
now making sure THE CARBON FIBRE LAYER IS SELECTED right click, invert selection and cut it so the carbon matches the shape of the wing perfectly
it doesnt look too good now, but this is where the magic happens
, still on the carbon layer look through the blending modes for overlay, see perfect carbon
merge the wing and the carbon layers together, now you can adjust the darkness/brightness depending on how you want it
there you go, it works on all colours and types of bodywork, like i said ive used this method and that donor many times and has never failed, the end result doesnt look as good as the hood as i did the wing quick for this tut, i tool alot more time getting the colours and everything perfect on the hood. Hope this all helps
