First, the pieces need to be smoothed out. The two best methods would be to either expose the pieces to acetone vapor or to coat it in "XTC-3D." Next, applying bondo to fill in imperfections. Once dry, the pieces are to be sanded smooth and even. Then, spray painted a base coat for paint to adhere onto. Lastly, several coats of colorful paint and a matte or glossy lacquer as a finish.