Using this ETUDE Dr. Mascara Fixer is easy. First, apply your regular mascara as usual. Then, take the fixer wand and gently brush it through your lashes from the roots to the tips. This will help set the curl and keep your lashes looking great all day. As for precautions, keep it out of reach of children and avoid getting it in your eyes. If it does get in your eyes, rinse immediately with water. For maintenance, make sure to keep the cap tightly closed after each use to prevent the formula from drying out. Store it in a cool, dry place.