How should I properly prepare sand stained wood before applying polyurethane?

To properly prepare sand-stained wood before applying polyurethane, start by sanding the surface with fine-grit sandpaper to remove any roughness or imperfections. Next, clean the wood with a damp cloth to remove any dust or debris. Allow the wood to dry completely before applying a wood conditioner to help the polyurethane adhere evenly. Finally, apply the polyurethane in thin, even coats, allowing each coat to dry before applying the next one.