First up is making the pattern. Taking advantage of my body double form, I draped and pinned cheap muslin to the form. I could cut and shape the muslin to the body double, pinning pieces together at seam lines until the form looks right. A sharpie lets me mark up the muslin until I've got the shapes and seams properly laid out. Next, I cut out the muslin pieces, and then pin them down to a work board where I can make the pieces symmetrical and make sure they join up properly. Finally, I pin the pieces to construction paper where I can lay out the pattern with seam allowances.
The final pattern consists of 4 pieces: the back pattern which is placed along a fold in order to cut a symmetrical piece, the front pattern which is used to cut one piece directly and then another piece with the pattern flipped (so there is one piece of fabric for each side), the back collar which is also cut along a fold similarly to the back piece, and the front collar from which two mirror image pieces are cut similar to the front body pieces. Now I'm ready for the fabric.