What I like to do for memorising an essay is to do it 2-4 sentences at a time.
I always write my essays on an online document but this same technique can also work on paper.
So I type out the 2-4 sentences that I am trying to memorise and read it through a couple of times. I then type out those sentences as much from memory as I can, but looking back at the original as many times as I need to make sure that I get it right. Once I've done that once I cover over the original and try to type it out again but without looking at any other writing this time. It's okay if you make mistakes: just write out as much as you can remember. Once you're finished, look back at the correct writing and recognise which parts you got right and which parts you got wrong. Repeat until you feel confident typing/writing those 2-4 sentences without needing to look at anything. then continue for the rest of the essay. This technique only takes me anywhere from 30 minutes to 2 hours depending on the length and complexity of the essay. It's also good to try again in a few hours or the next day to make sure you still remember.
I hope this helps!
