A sonnet is a 14-line poem, most often written using what is known as iambic pentameter and employing a fixed rhyme scheme. There are two recognized sonnet forms in poetry that set the base for any other sonnets that may be formed, the Petrarchan sonnet and the Shakespearean sonnet.
An important aspect of any sonnet is the structure. You can put together a proper sonnet by using iambic pentameter, which means that each line of the poem must consist of five iambic feet. The iambic pentameter rhythm follows this pattern: da-DUM da-DUM da-DUM da-DUM da-DUM. A poem cannot flow smoothly if it deviates in its meter.
The structure of a sonnet also depends on the type of sonnet. The oldest and arguably one of the most popular forms is the Petrarchan sonnet. This form is divided into two stanzas. The first consists of eight lines (known as an octave), and the second has six lines (a sestet). The line-ending rhyme scheme is abbaabba cdecde.
Another type of sonnet with a different structure is the Shakespearean sonnet, also referred to as the English sonnet. The form is commonly divided into four stanzas (or quatrains) and a couplet. The line-ending rhyme scheme for Shakespearean format is abab cdcd efef gg.