How do I find points of comparison between different kinds of literature?

Sometimes in the exam you will be given what seem like completely different texts, and asked to compare the two. Don't panic. Let's take as an example that you are comparing the representation of love in an extract from a Shakespearean sonnet and an extract from A Streetcar Named Desire. A play and a poem centuries apart may not at first seem like they have much in common, but you have to remember that there are themes and devices common to almost all literature that, with a little close reading, you will easily be able to link. Check what the texts are trying to do. Is there a representation of persuasion, use of rhetoric device? Is yearning and unrequited love represented in these texts, and if so, can you discuss the different ways they do it? As soon as you spot even a tenuous similarity, you will be able to build on it and from there, talk about points of contrast. Here is an example...

"In these extracts, both Shakespeare and Williams present the reader with an example of yearning for the beloved. Shakespeare utilises blasons, a staple of the sonnet form, comparing the beloved to nature in a way that shows the reader she is as necessary to him as sunlight or air. Williams relies more on stage direction and the power of the theatrical space to convey longing, describing Stanley's cries for his wife as "tortured" and physically representing the distance between the two with the use of props."