How should I apply polycrylic over an oil stain to achieve a smooth and durable finish?

To apply polycrylic over an oil stain for a smooth and durable finish, first ensure the stain is completely dry. Then, lightly sand the surface to remove any imperfections. Apply a thin, even coat of polycrylic using a high-quality brush or foam applicator, following the wood grain. Allow the first coat to dry completely before applying additional coats, sanding lightly between each coat for a smooth finish.