this reminds me off some of the dropkick schools that literally get 0 band 6's per year u can tell the students are completely different to other schools
do timed papers (even with shorter time limits to increase the pressure) and then find every single mistakes you make, and then consciously write down in a page/book how you could've avoided the mistakes. its a pain, but it works really well, ive pretty much stopped making silly mistakes in exams