A hood is basically a rectangle and the back is curved .
Making a pattern is easy.
just grab a coat with a hood and turn it inside out
put it on a peice of paper
Trace around the hood on 3 sides (where it meets the neck line I draw a straight conneting line instead)
(I'm on my way to work so I can draw and upload anything)
but try this http://khalida59.freeservers.com/drafting.html
under HOW TO SEW AND ATTACH A HOOD about in the middle of the page