“A story will only ever say one big thing. If (for example, and you are feeling very brave) you have to deal with four strands of a tale, make the intertwining of those four strands the one big thing you have to say. You may put twiddly bits into your story, but only if you can do so without departing from the one linear narrative you have chosen.”
— Rule No. 10, among the 25 simple rules for journalists drawn up by a Guardian editor. This one, I think, applies to all kinds of writing.
