* Syllables: Sonnets are typically written in iambic pentameter, which means each line has ten syllables, with the stress falling on every second syllable.
* Rhyme scheme: Sonnets usually have a specific rhyme scheme, depending on the type of sonnet. For example, Shakespearean sonnets have a ABAB CDCD EFEF GG rhyme scheme.
* Structure: Sonnets are typically divided into two parts: the octave (the first eight lines) and the sestet (the last six lines). The octave usually introduces the poem's main idea, while the sestet develops or resolves the idea.
Of course, there are exceptions to all of these rules, but they can be a helpful starting point for identifying sonnets.