Be honest: when did you last get actual feedback on a GP essay
not "good effort" or a mark with a tick. like actual, specific feedback that told you which paragraph was weak and exactly why.
for most people the answer is "a while ago" or "never really."
GP is genuinely hard to improve at because the feedback loop is so slow. you write something, wait two weeks, get it back with three comments, and you're supposed to somehow be better next time. meanwhile the exam is getting closer.
I've been working on something called EssayLens, it marks your GP essay like a Cambridge examiner would. gives you a score out of 50 and goes sentence by sentence flagging what's actually costing you marks. took me a while to build and I think it's finally at a point where it's actually useful.
first few essays are completely free, try it out at: essaylens.org