years ago i bought a book, about making patterns from clothes you
like, cant remember the name of it right now. but, if you already have
sewing knowledge so that you know what has to be cut on the bias,
straight grain, etc..you can pretty much lay out your pants, top,
whatever, get the sections as flat as you can, trace around the piece
then just add your seam allowance. I have had mixed results, but its
works most of the time.