How can I fix my forward neck from bad posture?

You are not going to get an instant fix on things like that. Your neck didn't suddenly appear forward overnight you had bad posture for years and that is why your neck is the way it is today. Walk straight, sit up straight and get you a good posturepedic pillow to help you at night. You keep it up it will eventually start to reverse itself. It may take you couple of years but you will get the effect you need.