How does one write? Well...you think "A E I O U and sometimes Y" and you go from there. Writing isn't rocket science, if it were then many of us would have won a big prize by now. So if it isn't rocket science then why, please explain to me, why people say "I wish I could write like you" or better yet my favourite, "I can't write." Well can you spell your name? If not then go back to kindergarten. Though if you can, then I shall rightly slap you in the face as you so deserve. If you can spell your name then I am sure you know how to write, so please don't be an ass and say "I can't write." I shall wish to slap you and will do so promptly.
Now lets move onto "I wish I could write like you." One. You can. Two. Stop watching so much damn TV and actually sit down with Microsoft WORD open, or with a pen and paper, and begin. Like I said, it isn't rocket science. Kids start scribbling when they are only months old, so...why can't you? I see no a difference.
If children can use their imagination to see a world in which you can't, then I suggest you start taking notes from them; maybe add a little sugar to your now bitter lives of adulthood. Peter Pan can fly, why can't you?