How to do well on GCSE papers

Heyy, in class I understand everything in science but in the end of topic tests I always do not that great. I’m predicted 3 grade 9s for science so obviously I want to be aiming for 90% in my tests. I also recently did the aqa specimen papers and got 72%, 75% and 78% (chem, bio and physics) which would be a grade 7/8 at best (using maths results last year) .
I want to study medicine so GCSEs are the first step.
How do you people get straight A*s or similar?

hey, so i got a* in chemistry and a in biology and physics last year and i found the cgp books really useful as well as pearson activelearn (online) to consolidate knowledge but the best way to practise technique is just to use past papers and mark schemes to learn how the exam boars wants it all structured

I think the main problem is keywords. You need to be more specific and detailed if you want to get those extra marks. Cuz it seems like you know the content, its just writing it in the way the mark scheme wants you to write it in, so the best way is just to do papers, mark them, and read the markers had to say about the paper. There are some things that you just have to learn, like definitions, word for word. Good luck in your GCSE's!!