Find a base for your poem. Have a look at a few existing examples to model your canzone poem on. The famous Italian poet Dante Alighieri wrote "The New Life," a 14-line canzone with 10 syllables in each line. Although this is one of many different canzone poems, with a very particular rhyme scheme, structure and theme, you can analyze it, take it apart and use it as a good example of how you can approach and write a canzone.
Define the topic. In your first two lines, determine the theme of your canzone. For example, "The New Life" begins: "Ladies that have intelligence in love, Of my own lady I will speak with you."
Introduce the purpose of your poem. State why you are writing the poem, what it is that you are trying to achieve. For example, "The New Life" continues "Not that I hope to count her praises through, But telling what I may, to ease my mind."
Convey the mood of your canzone poem. In the third set of lines, establish the mood and the stance you are taking. In "The New Life" example, this set of lines reads: "And I declare that when I speak thereof, Love sheds such perfect sweetness over me, That if my courage failed not, certainly, To him my listeners must be all resigned."
Give your poem a direction. Build on the direction of your poem and drill the purpose into the reader's mind during your fourth set of lines. "Wherefore I will not speak in such large kind, That mine own speech should foil me, which were base; But only will discourse of her high grace, In these poor words, the best that I can find" is how Dante Alighieri approaches the fourth set of lines.
End your canzone poem. Wrap everything up and leave the reader with an impact in your last two lines. "The New Life" concludes: "With you alone, dear dames and damozels: 'Twere ill to speak thereof with any else."