stuck in mocks

I’ve been consistently scoring around 40–50 in my mocks, but every time one section seems to drop significantly. My VARC has now fallen to around 20 marks, even though it was better earlier.
I’m not sure how to approach this. Should I focus on improving my weakest section first, or work on making all three sections more consistent? Also, how can I prevent one section from crashing in every mock?
Would really appreciate some advice on how to break out of this 40–50 score range.