Copy or print a list of prepositions to have beside you while you write the poem. Include preposition words like into, around, nearby, over, under, across, along, aboard and about to make a complete list. While you are compiling the list, think of some interesting nouns you could add to the preposition to make a phrase. Jot some of these phrases down to maybe use in your poem.
Choose a theme or story for your poem. Pick a place you know well, an experience you have had or an imagined place to describe, such as a location in a dream. Or, opt to write a poem on a distinct action, such as how you organize your backpack for school.
Invent prepositional phrases for your poem. Pair the prepositional word with a noun that will describe the theme of your poem. For instance, if you are writing a poem about a cruise you took when you were younger, you might come up with "aboard the white ship, or "fish under the water." If you are writing about how you prepare to dive into a swimming pool, you might write "Around the house/Over the pool/On the diving board/Under my breath, I pray/Into the water I spring."
Start the poem with a preposition that invites curiosity. For example, begin with the word "within a hand" or "beneath the deck" or "nearby the ghost" to situate a reader before you launch into a description of a place or thing. A first sentence might be "Inside the house, underneath the bricks, beside the garage, or along the muddy road."
Add adjectives around your prepositional phrases to create richer lines in the poem. For instance, in prose writing you could write "Inside the thin, purple house/Under the soggy eaves/Without a jacket/in spite of the cold.
Develop a list of senses about the place or thing you are describing in the poem. Use the sense of sight, smell, taste, touch and sound to guide you and your reader throughout the poem. For instance, for every object or place you describe, associate it with a particular color, taste or smell. For instance, the purple house may smell salty like the sea or, when crawling through it, feel gritty against your knees. The prepositions will come naturally.
Use prepositions you do not normally use. While inside, underneath and around are common prepositions, employ other prepositions--such as according to, amid, because of and toward--and turn them into phrases. The beginning of a dream poem might read like this: Inside the thin, purple house/over the sea/around the table a family gathered/ amid the sea-salt air/toward the moon/beneath them flying bats."