As someone about to go into Yr13, I know very well the struggle of balancing so many subjects at gcse. I did slightly different subjects (Spanish instead of French, didn't do drama or cooking but history and computer science) but I'll try and give some advice on revising them. I came out with 9s in everything but Maths, which was an 8, so hopefully I can help!
Subject Specific Advice:1. In terms of languages, I'll be honest I didn't revise at all for my Spanish exams but I would recommend just doing past papers and learning some high-level structures and maybe tenses - don't bother learning every word ever mentioned (like I tried to) because it's just not necessary.
2. For Geography, again I didn't do all that much revision at GCSE (noticing a pattern lol) but I'm taking it at A-Level and my current tactic is to make flashcards for the content, learn them to some degree and then practice exam questions under timed conditions and then focus on my areas of weakness.
3. Despite my grade, I absolutely HATED every second of both English Lit and English Lang. In terms of Language, the only thing you can really do is practice exam questions because there's no actual content to learn, everything's unseen so it's just a case of getting the exam technique right. For Literature, I'd say look at key quotes, themes, characters and context. It's probably not worth it to learn all the annotations and analysis for every single text because it's way too much to learn (I tried this and it didn't work) and again do lots of exam questions and get your teacher to mark them.
General Advice:1. Make a revision plan and
stick to it. Set yourself a few topics from different subjects to cover a day - the time scale depends on your homework load so I'd say 30mins to 1hr per topic, and maybe 2-3 topics a day each from a different subject to keep it varied.
2. The bad news is that the work-life balance will definitely be shifted a lot more towards the work part. I completely understand wanting to make the most of your time with your friends, but it's likely that everyone will be spending lots of time revising - maybe set up a study group after school? I know most of my lunchtimes were spent either in revision sessions or in a classroom with my friends with us all doing homework or stressing out. Obviously I don't know what your friends are like but sometimes it is best to take a break from them because if everyone is stressed then you're more likely to be as well - stress is definitely contagious.
3. Ask your teachers for help when you need it and address any issues as soon as they come up - the sooner they're dealt with, the better.
4. Also talk to anyone (teachers, friends, student support) when you're feeling overwhelmed. A memory that will never leave me is having a complete breakdown in an English class because I just could not answer the questions on the worksheet we were given on annotating The History Boys, and my mocks were coming up and I was just so overwhelmed my teacher didn't know what to do - it was the first time I'd ever struggled so much in a class and also the first time I'd been that stressed in front of a teacher. Especially when you're aiming for such high grades, the pressure is real and it's so important that you talk to someone and find things that relax you when it becomes overwhelming.
Sorry that this is such a long response, but I hope it helped, and good luck with your exams next year!