The sooner you respond to a spill (of wine, sauce, or greasy food), the less likely it is to stain, so blot—don’t rub!—as soon as you can with a clean, white cloth.
Try a spot cleaner or dry cleaning solvent approved for your type of upholstery to remove any remaining marks or spills that have turned into stains. Then blot the stain gently. After that, blot the area with a clean cloth or sponge dipped in clean water and wrung out. Repeat until the spot is dry, then blot it dry with a clean cloth or white paper towels.
It’s time to call a professional if the spot persists after two or three applications.