This exercise is at the core of Richard Lanham's Revising Prose, a book I highly recommend. The method takes writers into a sentence to consider how it is composed, to identify its weak elements, and to revise it to eliminate those elements. Not all sentences can be improved with this method, but many can. For homework, find any four sentences which can be improved by using the Paramedic Method; write them down on a sheet of paper, then improve them. A five dollar prize goes to the most atrocious sentence; students can write their own bad sentences.

• Circle the prepositions.
  
• Circle the "is" forms (is, was, were, are).
  
• Ask, "Where is the action?"; "Who's kicking who?"
  
• Put this "kicking" action in a simple (not compound) active verb.
  
• Start fast--no slow windups.
  As an example, here's a sentence:
  
  
  The car is on display in the museum next to the picture of James Dean because it is the same kind of car he was driving when he was killed in the car crash.

Because there is no HTML code for making circles around words, I'll make the "is" forms bold and put a line break for each preposition.

The car is
on display
in the museum
next to the picture
of James Dean
because it is the same kind
of car
he was driving
when he was killed
in the car
crash.

This approximates steps one and two. The question now is, "Where's the action?" The sentences buries one point of action in the prepositional phrase 'on display', and two others with the use of compound verbs in passive form: was driving and was killed. To bring that action to the front, and to start fast, the following sentence can stand as a rewrite.

The museum displayed--next to his picture--the same model of car James Dean crashed and died in.

A stickler might object to the sentence ending in a preposition, but to my ear the sentence reads better, sounds better, than the first version, and even better than the technically correct option that would remove the preposition from the end: The museum displayed--next to his picture--the same model of car in which James Dean crashed and died.

As with many examples, you can no doubt find a better way of rewriting the sentence. Feel free to try, but if you do, make it your fifth example.