To wrap food correctly with aluminum foil, you should use the dull side of the foil facing outward, which is in contact with the food. The shiny side has a non-stick surface and is not recommended for direct food contact as it may contain substances that could potentially leach into the food when heated. Start by cutting a piece of foil large enough to fully cover the food. Place the food in the center, then fold the foil over, crimping the edges to seal tightly. This will help retain moisture and heat, and prevent any potential cross-contamination.