George Orwell’s six elementary rules (“Politics and the English Language”, 1946):

  1. Never use a Metaphor, simile or other figure of speech which you are used to seeing in print.
  2. Never use a long word where a short one will do.
  3. If it is possible to cut out a word, always cut it out.
  4. Never use the Passive where you can use the active.
  5. Never use a foreign phrase, a scientific word or a Jargon word if you can think of an everyday English equivalent.
  6. Break any of these rules sooner than say anything outright barbarous.

This is on the economist.com styleguide