Visualization) Begin by thinking of a moment in your life which dramatically changed it.  Dwell in the memory until you can fully experience the heat of the moment. 
Description) Describe a few seconds of that moment. Include as many of the 5 of the senses each of your images as possible. 

Revision) Go back over the poem and make sure that each line has multiple sensory images. (sight & smell, touch/texture and taste)
Editing) Lace the important images into each other, cutting out wasted "connection based" words. Cut away images which are distracting to the main focus. 
Editing Goal) The poem must be 5 lines or less.