Can I Polish Pal Tiya Premium to make it smooth?
During the original sculpting, make the surface as smooth as possible.
Once fully cured, sand the surface with increasingly finer grit sandpaper. Begin with 60 grit then 80 then 220 wet/dry.
Use water with the 220 to get the best results. This will produce a nice satin surface.
If you choose to color your piece (Concrete stains) do it after the sanding. As with any cement based material, the color may appear mottled because of microscopic differences in surface density.
To bring up a high shine, use standard polishing waxes, however, these compounds will prevent any further colorants from adhering to the surface.
Have a look at this video