Pull the flowers off their stems and trim off any jutting plastic from the underside.
Cut two small circles from the felt - large enough to become the base for each flower, but small enough to not show through in-between the petals.
Use glue gun to attach each felt circle to the underside of each flower and press the felt to cup the flower's shape. In order to stop the top layers of petals from falling off, you may also need to glue in-between each layer, near the center.
Open the shoe-clips, place a daub of hot glue on the felt (I chose near the top of the circle to minimize the amount the flower protrudes from the edge of the shoe), and press the non-toothed side of the shoe clip into the glue. Squeeze more glue over that part to firmly attach it to the felt.
Allow to dry and remove gluey strings.
I'm liking this girly look on chunky clogs at the moment - found this pair at my local Goodwill and wanted to soften them up for the romantic look that's so in right now. I love the flower as juxtaposition to the organic wood of the soles.