Notes about making this hat: Instead of only using the elastic in the circle, I also added a chain which I slip-stitched into a loop (I thought this might be a good idea in case the elastic ever broke).
Another thing I did, was use a chainless double crochet stitch when I did the slipstitch with each new row (this makes an almost invisible seam).
I doubled my yarn (I used two skeins of 4 ply yarn, which makes the hat stiffer and a bit heavier).
My flower is oversized with 7 petals (I love the fullness of 7 petals as opposed to only 5).
I just purchased this amazing book on how to crochet different stitches. You will enjoy the many photographs and clear instructions. Enjoy!