This link is to an article in which Michael Morpurgo talks about how he combined elements of several true stories for his book, "An Elephant in the Garden":
I think it's interesting that although he could have written a version of the story set in England, he decided to challenge himself by setting it in Dresden.
The book has been adapted as a one-woman play, which premiered recently in Exeter.
The article includes this advice:
“It is important that you are passionate about the story. You have to really care. If you are doing it to get rich and famous – forget it. Writing will come to you, but the more research you do the better. There comes a moment when you must sit down and write. It’s in the writing that you find your voice. Once you start, your confidence and self-esteem build with it.”