grades in general (GCSE)

With english lang definitely read exemplar answers and compare these to your own work, then you know what to improve in order to write the best possible answers. There's youtubers like mr everthing english who's popular with aqa (i did eduqas so i cant give any specific advice, sorry 🥲)

Mr Bruff on youtube has some helpful english content, but that might just be for literature. I would read exemplars and watch videos that go over how the marking works - If you know how they mark it you'll probably know what to say

it’s okay, no worries, i have been doing some past papers but i also used the mark scheme to put my answer together, however i did get a grade 7 but i think that is because i used the mark scheme and i was very worried because i have been getting grade 3s the past 2 years

you're doing the right thing with past papers and mark schemes! maybe try writing an answer closed book, so without any notes and in timed conditions then give it to your teacher to mark. if there isn't enough time for your teacher to mark it then go over the mark scheme yourself and improve your answer yourself using that. this will be a good indicator as to how you will perform in the actual exam, depending on when your exam is. best of luck!