What I do if I want to memorise is memorise 1-3 sentences at a time
E.g. Memorise sentences 1-3
Write sentences 1-3 down
Memorise sentences 4-6
Say out loud 1-6
Write sentences 1-6 down
Memorise sentences 7-9
Say out loud 1-9
Write down 1-9
But I do it in paragraphs, if that makes sense
So once I have memorised all paragraphs individually, I'll write down the essay as best as I can without looking (have a peak if you're stuck)
Reread it and look at your mistakes
Write it down one more time and this should be perfect
It's always worked for me, and I end up memorising 1000-1200 words in 3-5 hours