Step 11: Attaching the collar
Continue carefully placing the neck hole edges between the collar sides and pinning, making sure to catch plenty of fabric when pinning. This may take a while as you need to go slowly to ensure that the collar is smooth and there are no puckers from the top or collar. Don't worry about folding under the edges at the back of the collar as we'll take care of that later. All you're worried about right now is the bottom edge of the collar.
Once pinned, sew the collar down to the top by sewing close to the edge of the collar to catch the most fabric (even though I pinned the fabric from the inside, I chose to sew along the outside so that I could ensure the fabric didn't pucker and that the needle caught the fabric from the collar). There will be a lot of fabric to sew through when sewing over the gathered hood edges, so go slow and take your time.
Once you've sewn all the way around, go around a second time, this time sewing about a 1/4 inch higher than your last seam.