Ok so:
for literature what i found useful was making a google doc analysing IN DETAIL each character in ur text, the themes, the key quotes and alternate interpretations of each character quote and main events. I also did AIC and i could give u a link to my google doc if u like but this will help SO MUCH make sure u read it often. For poetry i recommend that you chose 4 poems from the anthology that you like and analyse them thoroughly, again make sure u write more than one interpretation of the poems bc examiners love when you do that. These 4 poems will be ur main ones so make sure u can link these poems to whatever the question asks you or the poem the question asks u to compare it to.
For language make sure you read A LOT. The only way you can get a good grade is to have an extensive vocabulary. For example in section B it'll be a discursive writing question, you need to know how to write a piece of text in the form they're asking you to (blog, leaflet,speech). So make sure you read and are comfortable with these modes of writing. Also like literature id advise u to make a google doc and just fill it in with 'fancy' words and phrases just to catch the examiners eyes.
And for maths the only thing i can recommend is past papers bc they help so much. Mark them and see what topics you did bad on and go back and revise it and do more past papers, then repeat. With further maths honestly if you really do want it and think you'll benefit from it, do it. Your grades are really good already so I think you do have potential to do good in it. Hope this helps lmao