Roll out your polymer clay using a rolling tool. You want it to be approximately 1/16" thick when you are finished. Stamp the clay with rubber stamps if you want a design or textured look, otherwise leave it smooth. Use colored clay if you desire, otherwise you can spray paint the pieces after they have dried.
Cut out squares, rectangles or other shapes with your craft utility knife. Bake it in the oven for the amount of time specified by the manufacturer of the clay. Otherwise, use clay that hardens when it dries.
Allow tiles to cool from the oven or dry to harden completely. Spray paint pieces if you did not use colored clay to begin with. Place the tiles on newspaper in an outdoor area before spraying with the paint.
Glue tiles to the surface of the object you wish to mosaic. Use dimensional paint to fill gaps and work as a mortar.