How to write an effective ‘flashback’ (and bring your reader with you!)
First a wikipedia definition in case not everyone uses the same term: Flashback (narrative), in literature and dramatic media, an interjected scene that takes the narrative back in time from the current point The Writers Digest has a great post about this issue in which they offer 3 tips: Your flashback should follow a strong scene. (so the flashback should not be your FIRST scene, though lots of TV shows start that way, with a scene from the future that makes no sense, and t