just figure out if you're losing marks because of structure, your ideas themselves, or how you adapt to the question.
if you struggle with structure, just read exemplars and note how they order their arguments+ hand in lots of responses playing with different structures
if it's your ideas, read a lot of articles about your prescribed texts and also try to come up with personal ideas about your text
if it's adapting to the question, just expose yourself to a bunch of questions before the exam- don't write full essays, just think, how would i write this? write your thesis, points, evidence etc and if you feel as if your argument is lacking strength in any one area, perhaps try looking for stronger evidence/analysis for it