Related:

• Metaphors be with you!
• 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....
• cursor dipped in X n. There are a couple of metaphors in English of the form `pen dipped in X' (perhaps the most common values of X are `acid', `bile', and `vitriol').
  These map over neatly to this hackish usage (the cursor being what moves, leaving letters behind, when one is composing on-line)....