stuck at 70s in maths

I don't know how, but somehow i NEVER get past 75 percent in maths, like no matter how little or much i revise, somehow i'm always stuck in the 70s. i've never even made 80 but then again i rarely go below 70. i've been doing so many past papers etc and i still keep getting no more than 75 at most. i'm trying at least to aim for a 90 in past papers and then realistically if i get 85 ish in the real thing, i'm okay with that since that is usually a 9 for edexcel.... but it's actually ridiculous atp, i have no idea what to do. i'm literally stuck at a grade 7 in maths, sometimes an 8 if my teacher's just feeling nice, but there's only two months left and idk how to get the 7 up to a 9. and yes i'm desperate for 9s i'll literally do anything atp for grade 9's