A When I consider every thing that grows
B Holds in perfection but a little moment,
A That this huge stage presenteth nought but shows
B Whereon the stars in secret influence comment;
C When I perceive that men as plants increase,
D Cheered and checked even by the self-same sky,
C Vaunt in their youthful sap, at height decrease,
D And wear their brave state out of memory;
E Then the conceit of this inconstant stay
F Sets you most rich in youth before my sight,
E Where wasteful Time debateth with decay
F To change your day of youth to sullied night,
G And all in war with Time for love of you,
G As he takes from you, I engraft you new.
Working with the sonnet is about the architecture of the form, we allow the form to lead our ideas at first. Once we are more comfortable, we take over and press the form to fit what we want it to say. For now, though, simply follow along for the construction of the form.
The English sonnet is made of four parts - three quatrains and one couplet. Each quatrain has an iambic pentameter line construction, and each quatrain contains to alternating rhymes (as indicated by the letters on the left). Your first step is to come up with your rhymes. As you can see, you'll need seven rhyming words to rhyme twice. You may repeat a sound (like Shakespeare does with sky/memory and sight/night), but the form calls for coupling rhymes, so try to keep them apart if you do have to use the same sounds.
The couplet is either a counter claim to the rest of the sonnet or a commentary or witticism on what has come before it. Therefore, it is a good idea to construct this first - so you know what your sonnet will be talking about. So, construct the final rhyming couplet first. Then, proceed to creating - as best you can - the three quatrains. That's one sonnet down - two to go.
One of the most well-known sonnets is Elizabeth Barrett Browning's "How Do I Love Thee" which is composed in another sonnet form, the Petrarchan or Italian sonnet:
A How do I love thee? Let me count the ways.Step Three
B I love thee to the depth and breadth and height
B My soul can reach, when feeling out of sight
A For the ends of being and ideal grace.
A I love thee to the level of every day’s
B Most quiet need, by sun and candle-light.
B I love thee freely, as men strive for right;
A I love thee purely, as they turn from praise.
C I love thee with the passion put to use
D In my old griefs, and with my childhood’s faith.
C I love thee with a love I seemed to lose
D With my lost saints. I love thee with the breath,
C Smiles, tears, of all my life; and, if God choose,
D I shall but love thee better after death.
Barrett Browning breaks a bit with the rhyme scheme of a traditional Italian sonnet. The rhyme scheme is supposed to be abba abba cde cde. Like the English sonnet, it is a fourteen line poem in a single stanza, but, like the English sonnet, that stanza can be broken down into parts. The first eight lines, or the octave, present a problem or make an observation (i.e. "love sucks) and the last six lines, or the sestet, offer a solution or an answer (i.e. "it's not that bad" or "could be worse, could be raining"). As with the first sonnet, you should choose your rhymes first.
You'll want to decide on a subject to explore with a question and an answer. Try to ask something that begins with a "Should I...?" (i.e. Should I go on? Should I pursue him/her? Should I have hope?). The response can directly address the question, or you can get all Yoda-ish and offer something a little more enigmatic, ethereal. Compose the octave and the sestet as best you can (probably best to work out the octave first)... and when you are done, it's time to move on to the final sonnet form.
After composing two sonnets, you ought to start understanding why this form is so popular - it limits you to a tiny space to explore an idea, but gives you enough room with the rhyme scheme to work out a fairly detailed thought. Here, Edmund Spenser uses an allusion to Homer's Odyssey to launch into a commentary on his relationship in "Penelope for her Ulisses sake":
A Penelope for her Ulisses sake,Step Five
B Deviz’d a Web her wooers to deceave:
A In which the worke that she all day did make
B The same at night she did again unreave:
B Such subtile craft my Damzell doth conceave,
C Th’ importune suit of my desire to shnone:
B For all that I in many dayes doo weave,
C In one short houre I find by her undonne.
C So when I thinke to end that I begonne,
D I must begin and never bring to end:
C For with one looke she spils that long I sponne,
D And with one word my whole years work doth rend.
E Such labour like the Spyders web I fynd,
E Whose fruitless worke is broken with least wynd.
Spenser sort of takes the Shakespearean sonnet and mixes it up with a rhyme scheme that allows the quatrains to link to one another naturally (the rhyme scheme is abab bcbc cdcd ee as shown to the left of the poem). Since the linked quatrains create all of these couplets before the final couplet, the final couplet reads as a normal portion of the sonnet rather than an answer or commentary. As before, you'll decide on your subject matter and, of course, rhymes - you only need five (thank Spenser!).
Compose your final sonnet in this exercise by beginning with an allusion as Spenser does. If you need a refresher on how allusion works, check out the Allusion and Irony Exercise. The sonnet itself, as Irena Praitis points out, "...Given how frequently it appears, is almost inherently an allusion in and of itself. Simply choosing the form creates an automatic connection with literary tradition. Subject matter isn't the only way to build allusion." However, for this exercise, do choose a subject matter allusion.