Usually my starting point is something that I've seen. It might be a painting, it might be an object. But they always start from a definite sensory experience.
Russell HobanThere is a tiger in my room,' said Frances. 'Did he bite you?' said Father. 'No,' said Frances. 'Did he scratch you?' said Mother. 'No,' said Frances. 'Then he is a friendly tiger,' said Father. 'He will not hurt you. Go back to sleep.
Russell Hoban