Related:

• Metaphors are similes. Similes are like metaphors.
• Take the bull by the hand and avoid mixed metaphors.
• Avoid tumbling off the cliff of triteness into the black abyss of overused metaphors.
  -- Grammar rules for the unenlightened...
• Mixed metaphors are a pain in the ass and ought to be thrown out the window. -- Writing Rule 27
• Keep your ear to the grindstone, your nose to the ground, take the bull by the horns of a dilemma, and stop mixing your metaphors.
  -- Grammar rules for the unenlightened...
• William Safire's Rules for Writers: Remember to never split an infinitive.
  The passive voice should never be used. Do not put statements in the negative form....
• coefficient of X n. Hackish speech makes heavy use of pseudo-mathematical metaphors.
  Four particularly important ones involve the terms `coefficient', `factor', `index of X', and `quotient'....