There is no specific method authors use to generate new and original concepts. Luckily, we re all capable of creating fresh story ideas. The trick is being able to recognize a concept and make it bloom. I like to think of story ideas as flowers. You have to grow them yourself.
Some ideas begin as tiny seeds.
It takes time and nurturing before they grow into stories. Some ideas arrive in full bloom, ready to be written. There are even transplanted ideas. This happens when another writer is generous enough to pass along few seeds. But you shouldn t count on that.