From all of the books and posts on the forum that I have read, there are three keys that can enable you to grow taller or manifest anything that you want:
The belief that it is indeed possible to grow taller and the faith that even though you cannot see it yet, it will come to you. You must have faith in the unseen. The third one is feeling, you must feel as if it is real, that you are already the height that you desire.
Feelings is the key to impress your subconsious, who is responsible for maintaining your health, taking care of the cells of your body. So this is the chief that you want to address if you want to grow taller. Some people have been cured just by believing that they are, call it placebo if you want, but this is how it works.
Everyhing that happened to you until this moment is the result of what you have previously thought. Reality is just a reflection of your inner world. Nowadays Science tends to back up this idea, with quantum physics, our thoughts have frenquencies and they can affect particules, and what are we made of ? Atoms and particules.
Thus by changing our state of mind we can affect our reality and change it. If some facts can change your state of minds, changing your state of minds can change facts. It is that simple. So to grow taller, you must believe that you are already tall, you need to live as if your wish had already been fullfilled .
Before you are going to bed, relax breath deeply until you reach a state where you are half awake and half asleep.
Once you are in this state start to imagine how it would be like to be the height that you desire. How would you feel ? Visualize the people that you know congratulating you for being taller and see how amazed they are that you grew.
Hold on to that feeling and dive into it.
I would advise you to write down a scene that would take place once you grew, so that your mind is not wandering around while you are imagining. Once you have that scene, loop it in your imagination, until you fall asleep in it. While you are visualizing try to integrate every of your senses into your imaginary scene and try to make it as real as possible. Feel the joy and satisfaction of being tall, or whatever you would feel if you were. I know that some people have trouble to visualize, and if this is your case, focus on the feeling, the gratitude of having received what you asked for. I think this is truly the key, more than visualizing.
Visualizing whitout any feelings will lead you to nowhere.