How much detail do I need to go into in my essay plan?

Your essay plan should not take up too much of your time, but at the same time it is essential you have a plan. It will provide for a more organised essay and will serve as an outline of a structure you can lean on during the exam, rather than having to make it up as you go. It can also be a good space for you to jot down important bits of quotes or secondary literary criticism that can jog your memory and can de-clog your mind so you can focus on a good analysis, rather than recalling quotes. Therefore, do not spend too much time, definitely no more than 10 minutes on the plan, but have a rough outline with anything that you find essential to put in the essay.