Playing roughly with your cat encourages her to use her teeth and claws on people, a difficult habit to break. Cat scratches and bites are prone to infection, so discourage kittens and cats from engaging in rough play with human companions.
Sometimes rough play can be redirected onto toys. Distracting a cat with an interactive toy can stop some playful attacks. Providing your cat with plenty of toys helps keep her occupied and reduces her motivation to attack you.
If distractions don't work, try making a sudden loud noise. Don't hit, slap or kick your cat. Such physical punishment is inhumane and often makes the problem worse.
You must learn to distinguish rough play from true aggression, where the cat's motivation is to do harm. Aggression can be caused by illness, pain, fear or territoriality; your cat may also redirect aggression aimed at another animal toward you. Aggression is a serious problem. Consult your veterinarian before referring the situation to a certified behavior specialist.