I need to improve my chemistry grades; I want to do medicine

I’m in year 12 and I want to do medicine.
I’m currently getting D’s and E’s in chemistry, despite getting a 9 at GCSE.
I really, really need to improve my grades in order to get at least a predicted A in chemistry.”, any tips on how I could do this??
I am studying AQA chemistry
Please help!!!!

watch allery chemistry on yt bosss and do questions if u need to