To use this liquid foundation concealer, first make sure your face is clean and dry. Squeeze a small amount of the product onto your fingertips or a makeup sponge. Gently pat or blend it onto the areas you want to cover, like blemishes or dark spots. It's easy to apply and gives a natural look. As for precautions, avoid contact with eyes. If you have sensitive skin, it's a good idea to do a patch test on your wrist first. To maintain the quality of the product, keep it in a cool and dry place, away from direct sunlight. Don't leave the cap off for too long to prevent the product from drying out.