The last item I made when us cousins had a DIY girls night (see here) was a rose ring. Not surprisingly, this one was a bit of a challenge. If I remember it correctly, this was my fourth or even fifth try. The materials I used for it was a chunk of clay and a metal ring. There are many many DIY guides on youtube on how to do it (here is one e.g.). What I do want to add though, is that it is easier to work with the clay when it's cold. Also, we used superglue to glue the rose to the ring.
I definitely recommend it - after all, you can never have too many accessories :-)