Dip both hands in a bowl of cold water and ice cubes. "The cold water will freeze nail polish, seal, and harden it quickly," said Belinda Rivera, a nail specialist in Austin, Texas. Remove and let your nails dry for 2 minutes, then dip again into the cold water for 3 minutes. It is enough to make nail polish to harden completely.
Another way: Brass nails with cold air from a hair dryer for each color layer to dry.
Quick tips: nail polish that has long will usually dry because of the time can make the nail polish was so thick and finally dried. Shake the bottle of nail polish when the nail polish started to change color or separate from the oil.