I used fimo a coloured acrylic clay that hardens in the oven.
I used an ivy leaf cutter that is used to make cake decorations.
Once the leaves were cut to my satisfation I carefully cut into the blank side of the leaf the shape of the rune, macking sure not to cut all the way through the thickness of the leaf. Then using very thin rolled fimo oof a different colour I inserted it as best I could in the cut fimo, and patted it gentley down, trying not to remove the leaf veins on the other side.
When I was happy with my runes, I curled the edges of the leaves slightly and poped them in the oven for the alloted time.
My runes are not as robust as wood or stone, I take this into account when using them.
They work really well for me, and I have managed to keep and use them for a few years now