It may help
to group a bunch of your flowers together, then use a small
dome-shaped object (in this case a 1/2 teaspoon) placed at the
center. Flip over the flowers, with teaspoon underneath, and place a
heavy open object on top of your petal edges. I found a thread cone
does the trick!
The longer you leave this, the better the
shape, so I left my sit overnight.