What do icebergs have to do with writing anyway? Quite a bit actually if you know about Ernest Hemingway’s famous ‘Iceberg Theory’ which is also known as the “theory of omission”.
‘If a writer of prose knows enough of what he is writing about he may omit things that he knows and the reader, if the writer is writing truly enough, will have a feeling of those things as strongly as though the writer had stated them. The dignity of movement of an ice-berg is due to only one-eighth of it being above water.’ Ernest Hemingway
This is an amazingly clear description of the principle of ‘show, don’t tell’ in writing. Instead of telling a reader all about what our characters think, know, realize, remember, want and so on, we should be using action as well as sensory details such as smell, taste and sound to draw readers into the story.
There will always be some ‘telling’ that takes place in a book, especially during dramatic or action scenes. As with any art, a balance of pace, rhythm, even tone can make a story flow without ‘overwriting’ or explaining every moment.
Trust your reader to ‘get’ what you’re trying to convey to them and let your characters draw them into the story by their own experience on the page. Keep extraneous details from crowding out what’s important and ‘be’ an iceberg.