need some advice, please be kind

You still have a few months, try not to panic. The best thing you can do for yourself is to just put as many hours into work as you can.

Doing even just 1 extra hour a day to what you think you want to do will end up being almost 100 extra hours in a few months.

Speak to your teachers about your tests and ask them what you could improve on. Try to do mock papers, especially ones that you can easily mark yourself (STEM subjects).

You still have enough time to do well as long as you make sure to keep your head down and work hard

Try not to stress, trust me from experience it will only hinder your concentration.
For maths, I suggest using GCSE Maths Tutor for explanations and Corbett Maths for questions.
English, perhaps speak to your teacher/s in order to find a suitable structure that will ensure that when answering the questions it will be simpler and clearer. For remembering quotes use flashcards and place post it notes in places you commonly do daily tasks in or near.

Heyy im also a year 11, here are some things that have helped me:
•maths- use maths genie, it’s so helpful it has practice questions and videos! Each topic is graded aswell
•science- past paper questions(on specific topics) on the website physics and maths tutor. Also watch free science lessons or cognito YouTube vids for understanding content
•English literature- watch analysis videos on YouTube, they help me analyse specific themes/characters/poems and after watching only a few, I learnt how to analyse with better language and depth too.
•English language- just practice, find example descriptions online and put them in ur writing, get it marked and continue doing it. Then start writing in timed conditions, you can use phrases from all your practice essays. Make sure you get your practice essays marked and get feedback!
Hope this helped💕 this is what I did before my year 11 mocks to get me atleast two grades higher than all of my year 10 mocks