Tape Trick: This one is always a fun. It works good for any designs impressed into the clay (obviously stamped images work great). Use a brush to fill the pressed-in lines with mica powder. It's ok to be sloppy. Use several colors if you want to. Carefully blow away any excess mica. Now use clear tape to peal away the mica from the surface of the clay, leaving it only in the impressions. You may need to use several pieces of tape in order to get all the surface powders off.