gcse i want to get 7s and over

i have always been an average student from primary school, so do i still have a chance to get 7s and overs in subjects like; biology, chemistry, physics, maths and both english?

Yes 100%! I'm no scientist and I dropped all of the sciences after GCSE (I did nearly take Biology, though) but I managed to get 88 in Combined Science, with 9s in four of the six papers (both biology, one chemistry and one physics.) If you put the work in, you'll be fine. I've made some notes by subject which may help with this.

English Literature (which I got a 9 in and am taking for A Level)
Read the texts, really really well. Read chapters or poems ahead of the lesson, and have a colour scheme for annotations (language, structure and other) and underline or highlight anything you think is important or interesting. Establishing a list of key themes for each also really helps, then you know what you are looking out for. Make your notes based on the presentation of themes or characters in each chapter, a summary with a few quotes, either as you go or a little while after finishing the text. Either is worthwhile and good revision. Re-annotating key passages and poems is really good for revision too. Make annotations on copies of the texts, so buy copies of your set texts and print out the poems. It makes it a lot easier when writing essays. Essays and essay paragraphs and essay plans are your best friend when it comes. English Lit is very skills-based - you can't learn analysis - so practice writing about themes and texts. Before my exam, I had planned or written essays on every possible theme or combination of poems, some of them several times. Having a format to stick to for analysis often helped, so use whatever paragraph structure your teachers recommend. Mr Bruff is also great!

English Language (also got a 9) & Maths (got a 7, but had been getting 8s and 9s for all of Year 11)
Practically as above, but all practice. Pay attention in class. Do the work to the best of your ability every time and you will build up the skills that you need. There are lots of workbooks from CGP or the exam boards that you can buy and I highly recommend them; I had many and they helped a lot. And learn your formulas.

Sciences (Combined science: 88)
Make detailed notes with diagrams after lessons in whatever style suits you. There are many science YouTubers that you can watch, both for revision and if you don't understand topics, but you can't just watch the videos; take notes or do the problems alongside them, or answer some questions on the topic afterwards. The main thing with sciences is understanding, the GCSE papers are full of application questions meaning that you really have to understand the content, not just be able to recite the process of mitosis. Invest in workbooks, that is your best means of practising the application of knowledge and testing your understanding of content.

Yes 100%! I'm no scientist and I dropped all of the sciences after GCSE (I did nearly take Biology, though) but I managed to get 88 in Combined Science, with 9s in four of the six papers (both biology, one chemistry and one physics.) If you put the work in, you'll be fine. I've made some notes by subject which may help with this.

English Literature (which I got a 9 in and am taking for A Level)
Read the texts, really really well. Read chapters or poems ahead of the lesson, and have a colour scheme for annotations (language, structure and other) and underline or highlight anything you think is important or interesting. Establishing a list of key themes for each also really helps, then you know what you are looking out for. Make your notes based on the presentation of themes or characters in each chapter, a summary with a few quotes, either as you go or a little while after finishing the text. Either is worthwhile and good revision. Re-annotating key passages and poems is really good for revision too. Make annotations on copies of the texts, so buy copies of your set texts and print out the poems. It makes it a lot easier when writing essays. Essays and essay paragraphs and essay plans are your best friend when it comes. English Lit is very skills-based - you can't learn analysis - so practice writing about themes and texts. Before my exam, I had planned or written essays on every possible theme or combination of poems, some of them several times. Having a format to stick to for analysis often helped, so use whatever paragraph structure your teachers recommend. Mr Bruff is also great!

English Language (also got a 9) & Maths (got a 7, but had been getting 8s and 9s for all of Year 11)
Practically as above, but all practice. Pay attention in class. Do the work to the best of your ability every time and you will build up the skills that you need. There are lots of workbooks from CGP or the exam boards that you can buy and I highly recommend them; I had many and they helped a lot. And learn your formulas.

Sciences (Combined science: 88)
Make detailed notes with diagrams after lessons in whatever style suits you. There are many science YouTubers that you can watch, both for revision and if you don't understand topics, but you can't just watch the videos; take notes or do the problems alongside them, or answer some questions on the topic afterwards. The main thing with sciences is understanding, the GCSE papers are full of application questions meaning that you really have to understand the content, not just be able to recite the process of mitosis. Invest in workbooks, that is your best means of practising the application of knowledge and testing your understanding of content.