How can I prepare for an exam or essay that requires comparing two texts?

Firstly, you should check your syllabus to see what stipulations there are about the texts you are comparing. Does one have to be a poem, or pre-1900, do you have to compare two different mediums of texts such as novel with a poem? Once you know what you are expected to do in terms of the syllabus - you can select your texts. It may be the case that you are drawn to one text in particular and if you have enjoyed it will likely mean that you'll feel more comfortable answering questions about it in an exam setting. If you do have one text which you know you would like to write about then you should think about the themes within it that will help you select your comparative text. For example, if you want to write about Shakespeare's Macbeth, think about it's themes such as ambition, power, gothic drama and then have a look and see what other texts on your syllabus share these themes for example you could select Angela Carter's The Bloody Chamber as a contemporary gothic comparison.Approaching an comparative essay or exam question thematically means you will have a strong focus during your revision period. So, you could draw up a mind-map with Macbeth in the middle and lines leading out of it which show it's various themes, and then list quotes underneath that you think are strong evidence of those themes. You can then do the same with the other text you select (in this example the Bloody Chamber) and look at the cross-over and what they are doing differently or share. Both Macbeth and the Bloody Chamber are considered Gothic text but how do they show an evolution in the gothic genre - if you consider the fatal power and ambition portrayed in the character of Lady Macbeth this could lead you to also demonstrate and explain how the female characters in Carter's The Bloody Chamber respond to power and ambition and why the historical setting of the novel means these are portrayed differently. Examining the difference and similarities in these portrayals will allow you to more easily evaluate the literary techniques deployed in the writer's text and examine both why and how they impact the text differently.