So here are some tips that I've discovered along the way:
First, I want to mention that I'm using a freezer paper method for the paper piecing. It's my go-to method for all paper piecing, but I think it's an especially easy way to paper piece the arcs for this quilt. The pattern is transferred to the freezer paper by stitching through the pattern and several layers with a sewing machine and no thread. The paper is folded and the stitching is done next to the fold, but not into the paper. Since you're not stitching the paper, it is easily removed and reusable.
After each blade is added, the seam allowance is trimmed to 1/4" and the next blade is ready to go. There are tutorials online for this method. Just do a search for "paper piecing with freezer paper".
Once all the blades are added - you have this ready to be trimmed.
Trim each of the straight edges exactly 1/4" from the edge of the freezer paper.
I found that trimming the curved edges 1/4" made it a little difficult to turn under the edges for appliqué with all those seams. I'm trimming them with scissors, eyeballing a bit over a 1/4" - probably just under 3/8". In fact, the inside, smaller curve is not even turned under - so 3/8" is fine.
This is a tip I got from Jennifer and REALLY helpful. You'll sew a square to one end of each arc and then sew 2 arcs together at the squares. Start and stop your stitching 1/4" from the edge (right where your freezer paper ends), backstitching to secure.
The "free" seam makes it much easier to sew the two arcs together and turn under the outside edge for appliqué.
When pressing the end squares - press the seam allowances from one square toward the arcs and the other toward the square. This will nestle your seams when these units are sewn together.
The outside curve is turned under for appliqué to the background. I ironed it under and used starch just like I explained here and prepped the center piece the same way. Once the edges are turned under and the starch is dry, I remove the paper. The center "eye" is appliquéd to the hole in the arc shape.
That's a little tricky to handle, so I start by laying my arc shape nice and flat on a piece of foam board. I position the center eye and pin it in place directly into the foam board. With it pinned to the board, I baste it in place around the edges. It's a little awkward because it's pinned to the board, but doable and keeps it nice and flat. Then I can remove it and appliqué it in place.
Hope that helps! It's really not a difficult quilt to make - lots of different steps - but sooo pretty! Let me know if you have any questions!