How do I move from the 6/7 grades

Got 6/7 in all my mocks but can’t seem to get any higher? Not the fact I’m doing bad sometimes if it’s oike english then I feel like there’s
No real way of improvement. My improvement rate has gone mental since start of year 11 , only received more than a 6 in English’s and media. And now working more than a 6 in all except Spanish and getting mainly 7s but how do I get the 8/9s it seems almost impossible only time I’ve recieved one is when I got full marks in media and got an 8 due to adding coursework which was a 7 in it