Plath is hard to put into a box; her poetry entirely unpredictable.
Her frequent tones seemed to expose herself at varying times of her life. These would portray brillance, detachment, worry, promise, disturb, and wrong. Because so many of these ideas seem polar opposites of each other, her critics and analysts often suffer great confusion with her sufferage. How could her life have been expressed through her poetry to be so distraught when she was also so well off?
Common devices Plath employed included the symbol and the image to great degree. Often, she used ordinary everyday items that might seem silly to consider worth literary merit. She incorporated the use of white regularly to symbolize purity and innocence. The use of babies and corpses, life and death, and the growth of trees and flowers regularly appears to compliment a developing theme. Her work in "The Mirror" takes the reflective quality of a mirror to explore the limitations of reflection as well as the ability to tell the truth, an often sore occasion.
Themes that also regularly appeared in her poetry varied. Much confession can be found in Plath's poetry that suggests she must have struggled with guilt. Likewise, she underwent severe depression more than once in her life and for good reason, she had endured criticism and a horrible miscarriage. She imagines herself as less than others and this creates repeated themes of guilt, inaptitude, insufficiency, and ingraditude.