Imagery is certainly one literary device Austen uses to make Sense and Sensibility effective. Unlike most of Austen's work, she uses imagery in detail to describe things such as Barton Cottage, the scenery, and even certain scenes. Below is a description of how Austen used imagery to effectively describe a particular scene.
Austen uses a lot of effective imagery to paint particularly dramatic moments. One example of this can be seen in the moment that Mrs. Jennings relays the story of Fanny Dashwood finding out about Edward Ferrars secret engagement to Lucy. As Mrs. Jennings relays the story to Elinor, she paints it in vivid detail. For instance, we learn that when Lucy's older sister Anne, sometimes called Nancy, informs Fanny of Lucy and Edward's engagement, Fanny immediately falls into "violent hysterics," which serves to paint a very vivid image of the scene taking place. In addition, she describes Lucy as falling into a "fainting fit" and Nancy crying bitterly on her knees, both of which are also very vivid images (Ch. 37).
Another literary device Austen employs to make the novel effective is diction. Austen frequently uses diction to express emotions. For example, when Marianne first learns that Elinor has known of Edward's engagement to Lucy for four months, in bewilderment, she asks Elinor, "How have you been supported?" Supported is an excellent word choice because it paints the picture of Elinor needing to sustain her weight on something, as if what she has suffered has taken all of her strength. Other good diction choices are "suffer" and "disappointment," which show just how much Elinor has been hurting. In addition, the words "triumph" and "exultation" show just how much Elinor feels Lucy to be at a greater advantage than Elinor to be engaged to Edward (Ch. 37).