How should I properly finish polyurethane to achieve a smooth and durable surface on my project?

To properly finish polyurethane for a smooth and durable surface on your project, follow these steps:

1. Sand the surface with fine-grit sandpaper to remove any imperfections.
2. Apply a thin coat of polyurethane using a high-quality brush or applicator.
3. Allow the first coat to dry completely before lightly sanding with fine-grit sandpaper.
4. Apply additional coats of polyurethane, sanding between each coat for a smooth finish.
5. Allow the final coat to dry completely before buffing with a fine-grit sandpaper or steel wool for a smooth and durable surface.