Literary techniques are certain constructions an author uses to form a story and that give artistic meaning. Many literary techniques are found all throughout A Midsummer Night's Dream.
One technique Shakespeare uses in particular is dramatic irony. In dramatic irony, the audience is aware of something that the character, or characters, is not aware of. In the play, the audience knows that the reason why both Lysander and Demetrius are now pursuing Helena instead of Hermia is due to the fact that Puck enchanted Lysander with the magic flower by mistake. As a result, both men feel that they are legitimately in love with Helena while the audience knows that that is not true. Lysander even claims that his reason has guided him to believe that Helena is the better woman than Hermia, as we see in his lines, "The will of man is sway'd, / And reason says you are the worthier maid" (II.ii.117-118). In addition, Helena disbelieves their sincerity, even accusing both men plus Hermia of conspiring to mock her.
A second literary technique Shakespeare uses is rhetorical schemes. In particular, Shakespeare uses hyperbaton a great deal, which is purposefully putting words in an unexpected order. Specifically, Shakespeare frequently switches the order of the subject and verb. One example is seen in Helena's important, theme-depicting line found in the very first scene, "[T]herefore is wing'd Cupid painted blind" (I.i.240). In this sentence, "wing'd Cupid" is the subject of the sentence. In normal word order, the subject begins the sentence followed by the verb. If we were to write this line in normal word order we would have, "Therefore, wing'd Cupid is painted blind," showing us that Shakespeare indeed employs hyperbaton by intentionally inverting the word order.