How do you find the rhyme scheme in a poem?

Rhyming is the repetition of sounds in two or more Words or phrases. Here are some examples; the Words, "Boy", "Coy" and "Toy" all rhyme, they all end in "oy". Not all rhyming Words end in the same letters, what is essential to a rhyme is that the sound at the end of the Words is the same, for example; "Mane", "Drain" and "Campaign" all rhyme but none of them have common spellings.