Find a word or series of words that you feel most clearly states the main idea of the poem. This may be a bit of dialogue, a sound, an image or even nonsensical words. This will be the basis of your refrain.
Determine the length of the refrain. Some refrains, like those found in popular music, can be very short or very long. Consider whether the point you are making will be served best by a long, descriptive refrain, or a short, concise one.
End each stanza with the refrain. This type of refrain helps bring the focus back to the idea asserted by the refrain. The reader reads each section and at the end is reintroduced to your main idea.
Repeat the refrain several times in a row. This type of refrain is common in chanting, a type of spoken poetry common to many cultures. Chanting refrains can become meditative. The reader may become so accustomed to the words that after a while they begin to see them in a new light. A refrain repeated many times on the printed page can form visual pattern, like a painting.
Repeat the refrain within the stanzas. The refrain may appear at regular or random intervals in the stanzas, reasserting and weaving itself through the ideas and narrative. A refrain can even disrupt the flow of the poem, creating a jarring effect that can help break the reader out of complacency and help drive home the message of the refrain.
Place the refrain at the end of a series of related stanzas. This placement of the refrain will act like a divider between sections of your poem. When one idea has been communicated through a series of related stanzas, the refrain marks the end of the ideas shared by these stanzas and prepares the reader for the ideas the next stanzas will introduce.