Which literary devices does Plato use in Theaetetus?

First, one should note that in Platonic studies, scholars normally use Stephanus numbers to refer to the location of passages. Stephanus numbers actually refer to the pagination of the 1568 Stephanus edition of Plato (the first modern edition or "editio princeps"). Most translations used in scholarly context have Stephanus numbers printed in brackets in the text or alongside the text. These are numbers in the form of a number followed by a letter, which is...

First, one should note that in Platonic studies, scholars normally use Stephanus numbers to refer to the location of passages. Stephanus numbers actually refer to the pagination of the 1568 Stephanus edition of Plato (the first modern edition or "editio princeps"). Most translations used in scholarly context have Stephanus numbers printed in brackets in the text or alongside the text. These are numbers in the form of a number followed by a letter, which is occasionally followed by a line number, referring to the page, column, and line of the Stephanus edition. Thus one would refer, e.g., to Theaetetus 150c4. This way, scholars can talk about specific passages in the Greek text or in various different translations even if they are looking at different editions.

You might want to focus on finding similes and metaphors. A simile is a form of explicit comparison using words such as "like" and "as" to signal the act of comparing (e.g. "My love is like a red, red rose") while a metaphor is an implicit comparison ("Till age snow white hairs on thee"). 

One of the most important extended metaphors of the dialogue may be found at 150b-d, where Socrates compares himself to a midwife. This is one of the best known passages in the Platonic corpus describing the nature and purpose of Socratic elenchus.

An example of the use of simile is found at 180e-181a, which compares students of philosophy torn between Heraclitean and Parmenidean ontologies to boys playing a game (probably dielkustinda).

As you read through the dialogue yourself, you will note that one of Socrates' most common types of argument uses analogy, and thus the dialogue abounds in use of simile and metaphor.