Before writing any form of poetry, familiarize yourself with the rhyme scheme. For instance, the rhyme scheme "a-b-a-b" means the first and third lines rhyme with one another while the second and fourth lines rhyme with one another. Sonnets are written in iambic pentameter, which means they require 10 syllables per line. The pattern for iambic pentameter sounds like "da DUM/da DUM/da DUM/da DUM/da DUM." An example is: "If you would put the key inside the lock."
Petrarchan or Italian Sonnet
The first eight lines of the Petrarchan sonnet are called the octave; it's rhyme scheme is "a-b-b-a-a-b-b-a." The second section is called the sestet. While writing the sestet, include lines c d and e. The only thing you are not permitted to do is end with a two-line stanza -- called a couplet -- such as "d-d" or "e-e." An example of a Petrarchan sonnet is William Wordsworth's "London, 1802." It includes an octave and a sestet with the appropriate rhyme scheme.
While writing a Spenserian sonnet, use the rhyme scheme, "a-b-a-b-b-c-b-c-c-d-c-d-e-e." The lines are split into three quatrains, which are four-line stanzas. The rhyme scheme for the first stanza is "a-b-a-b," while the rhyme scheme for the second stanza is "b-c-b-c," and for the third stanza, it is "c-d-c-d." The last line is a couplet with the rhyme scheme "e-e." Edmund Spenser created the Spenserian sonnet.
The Shakespearean sonnet is the easiest sonnet to write. It consists of three quatrains and a couplet. The first stanza has the rhyme scheme of "a-b-a-b," while the rhyme scheme for second stanza is "c-d-c-d." The third stanza's rhyme scheme is "e-f-e-f," and for the couplet, it is "g-g."