I made a little tutorial for you it's easy. I use transparent polymer. That is the magic.
Step by step. 1 The basis of any polymer clay. What colors you prefer. 2 For surface coloring I use pastels-different colored flecks. 3 A thin layer of fimo gel. Not necessary if you use a pre-baked base. But i use it very often. 4 -Glitters , Mica , or what you like. (cool for effect) 5 IMPORTANT! A very thin layer of polymer clay. The best brand is transparent Cernit. It is the most transparent. After that, what I bake product. Throw it immediately into water with ice. Cernit will be more transparent.