You cannot write if you have not lived. This, I believe, is the only rule for writers, or any artist for that matter.
Stories are life from the writer’s viewpoint. So if the writer has not lived, there will be nothing to write about.
The very best writers are those who draw the most out of life, capture its little details and understand it fully. Writers take what they have learnt and share it with the world. Writers are teachers, writers are learners. Writing is a give and take process. To have written is to have lived. That is all.
Me being an artsy-fartsy, pretentious little child. See how the slightly old fashioned tone makes everything I say so much more serious? It’s true though, that the best remedy to writer’s block is a day spent outdoors!