Although I didn't study Business I did study English Lit and Bio, for me the best way to improve your english grade is to practice essay writing and asking your teachers to mark it. For most questions it will take an hour max and doing this once a or twice a week will honestly improve your grades so much. I personally when from getting a D in my y12 internal to a A by the end of Y13 just through writing mock answers. Another thing is to redraft your answers after your teacher has marked it. If you honestly don't have time to write out full essays then I'd rec writing short bullet points and planning answers as these help just as much. Make sure you're also timing yourself and be strict with this as timing is what always gets people in the real exam.
As for Bio what worked for me best was summarising each page of my booklet onto small post stick notes for all my booklets and then blurting it on paper and using a separate colour for any corrections or anything that I'd missed out. Once i was confident I'd do exam practice questions for each specific sub topic for example doing practice questions on photosynthesis only the best place to find these are maths and physics tutor. Most questions get repeated so its super important to do practice papers timed aswell. Lastly, space out your revision. For example, blurt the content that you revised a week later using short questions on anki notes to help ensure it stays in your long term memory.
As someone who procrastinated alot make sure not to just revise when your suddenly motivated the best results will always show through consistency. Make sure to remind yourself why your studying and set clear goals. Its either you do it now or regret it later.
Sorry if this was long lol, dont stress too much you got this!