The biggest problem of using vellum when card-making is fixing the vellum to the card.
The problem that I had with this one, was that I wanted clean lines, so on one side of the card there was no way of disguising any adhesive.
The solution in this case was to use brads to fasten the bottom right hand corner of the scallop circle to the card.
The card stock was Pink Pirouette, the vellum was cut using the Scallop Circle die which was then stamped in Versamark and embossed with white EP using the rose from the (by now current favourite) You are Loved stamp-set.
Flowers are cut in vellum using the Bigz L die Fun Flowers, with an Itty Bitty punched flower and a white brad in the centre.
(This is how all the flowers were attached to the card - thus fastening the vellum securely to the card without any adhesive, which would show through the white vellum.)
You may have to zoom in on this photo to see the detail.