I don't really like saying there are rules to writing, because someone somewhere, will prove me wrong. However, every now and then a convention in writing becomes so accepted that it almost becomes a rule. For instance - All stories must have form and proportion.
A plot must have balance. Stories that are in balance are things of beauty, get the balance wrong and they start to feel ugly.
- A plot should never consist of continuous desolation and emotional anguish. Readers soon tire of it, they become emotionally exhausted.
- Readers should always associate with your characters. Make this connection by ensuring that incidents are feasible for the situation and genre.
- The tempo of the story should vary - some scenes must be calmer than others.
- After writing a chapter containing a significant episode, give readers time to recover by writing a more leisurely scene - not a boring scene of course, but one with fewer disparities, fewer ups and downs.
- Make your story congruent with, yet larger than, life. Everyday life is mostly boring - readers of fiction want entertainment, not a documentary - and they certainly don't want lecturing.