Read the poem straight through. Look up any unfamiliar words in a dictionary. Get a feeling for what the poem is trying to say.
Read the poem aloud, or have a friend read it. Listen to how the words sound. Pay special attention to any rhyming words.
Write an "A" in the right margin after the first line. Also mark even following line that ends on this same speech sound with an "A."
The first new rhyme sound that occurs after line one gets marked with a "B." In all likelihood, this will be line two. Every line that shares this sound also gets the "B" notation.
Mark every new rhyme with the next letter of the alphabet. Be careful not to introduce unnecessary new letters. Check back to the beginning of the poem if you think a sound already has a letter to identify it.
Look at the fully marked-up poem. Notice any patterns in the rhyming. Determine if the structure adds anything to the meaning or feeling of the poem.