Want to get good at sewing tiny curves - make Barbie doll clothing lol!!
I find it works best to put the outer curve on the bottom, and then just ease the inner curve around as you sew. It's so much easier doing it with a 1/4" seam than with clothing where you have a 5/8" seam allowance to pay attention to.
Another trick is to cut the pieces a bit oversized, making sure to keep the arc exact. That way if you ease a bit too much or not enough, you can trim and still end up with the right sized block.
One of my goals last fall was to practice sewing circles - this was the result. (and another quilt using up my batiks)
I'm almost done with the borders for my SBS top. I have three of the sides sewn on, but have to do some fiddling for the four corners as I'm using blocks that ended up too large to use in the field, but they are not large enough for the 7.5" border.