How can i increase my height fast?

You can't :(: Unfortunately your body will grow at its own pace. The only think you can control is your posture which may make you appear taller. I believe you are still undergoing your growth spurt so hang in there and remember that you are perfect the way you are.

Platform shoes: At a listed age of 18, there is no way to "grow" taller fast.The growth centers that determine linear growth close after adolescence, at 16-17 in most females and 18 in most males.After closure, you can not grow taller. A single x-ray of your wrist/hand can reveal evidence of growth centers either open to more growth or closed.

Exercise, eat, sleep: Most people reach their maximum height in their late teens. Without nutritional problems or chronic childhood illnesses, height is largely based on genetics and parental heights. Aside from eating right, exercising, sleeping well, and being happy, there's not much a person nor his doctor can do to increase height. It is very unlikely for a girl to gain any more height in her final teen years.