How can I achieve a smooth and polished surface on finished wood through sanding?

To achieve a smooth and polished surface on finished wood through sanding, start with a coarse grit sandpaper to remove imperfections, then gradually move to finer grits for a smoother finish. Sand in the direction of the wood grain and use a sanding block or machine for even pressure. Finish with a fine grit sandpaper and consider using a wood conditioner or sealer for a polished look.