What should you do to ensure adhesion when painting over glossy finishes?

Sanding the surface to create texture for adhesion is the most effective method to ensure that paint adheres properly to glossy finishes. Glossy surfaces are typically smoother and can prevent paint from adhering effectively due to their non-porous nature. By sanding the surface, you create tiny grooves and imperfections that enable the new paint to grip better. This mechanical bonding enhances adhesion and reduces the chances of the paint peeling or chipping over time.

Using a high-gloss paint for coverage, applying paint without preparation, or using a primer that matches the final paint do not address the specific issue of poor adhesion on glossy surfaces. While primers can help in certain situations, they are not a substitute for the preparatory step of sanding, which is crucial for achieving a strong bond in this context.