Up until fitting my Crepe, I found the idea of a body graph (recommended by the book Fit for Real People) to be overkill. First off, the need for butcher paper put me off (of course, I've since thought of a ton of things you can use instead: Swedish Tracing paper, wax paper, freezer paper, the reverse side of wrapping paper...the list goes on & on).
When I fitted my muslin, I was sure that there is something up with my shoulders. But I wasn't sure what (other than they were uneven, but that isn't too big of a deal according to FFRP). Which lead me to doing my own body graph. I recruited DH to do the majority of the work ;) it turned out pretty well. And it was quite easy considering the insight that it gave.
It took me quite a bit of digging through FFRP (comparing my proportions to the "ideal" proportions) to get it all figured out, but now that it's done, I think I've got it down.