Hi, I'm currently doing my A levels for Biology, Chemistry and Spanish
1) You may not like this advice, but frankly, try to do as little as possible during the Y11 holiday and enjoy yourself. This is your deserved time off after working so hard for the GCSE. If you want to do smth, maybe watch introductory vids ab the gap from y11 to y12 on Youtube if anything, but I wanna stress that this is a special time that you'll look back on so don't waste it.
2) Bio and chem (and math,s according to my friends say) are hell. The gap is crazy, but you eventually lock in with the flow of it. For the sciences tbh it starts off really easy, bc all its just new things added on the easiest topics, i.e you learn that there's like 5+ more structures in cells, and you start learning ab electron microscopes etc, chemistry again similar, you build on GCSE topic 1 knowledge, but then at some point, if you are not on top of your work, it all becomes a bit hectic to try to learn, so maybe plan ahead ig by revising just a little bit maybe an hour or 2 initially. Can't say much ab maths other than there are some topics that make my friends very, very sad.
3) As previously said, keep on top of ur work, your future self will be happy, as y13 content Is building on y12 content, so y12 content fs needs to be locked
4) TBH it is a good idea, get some money on the side, and it looks good for uni applications. If you aren't really interested in making money like that, do what I did and work like an hour or 2 on the weekend for a charity shop, also looks really good on uni application and less time working, I've had friends work hours for minimum wage and because of that did not do so well in class/mocks etc.
5) Because A-level content is so large, if you are a flashcard person, start from the first lesson, bc I'm not exaggerating when I say it is a LOT of content. I also find that teachers teach horribly/ don't teach what's on spec/ teach extra things on spec, so it's worthwhile either buying flashcards or making them. I used a lot of videos to help me, Miss Estruch for biology and Allery Chemistry for chemistry, feel free to explore them and other channels. The important thing is to do a lot of PPQs and question practice, which you can find on PMT and other websites, tbh. Don't just rewrite ur notes, make them effective by bullet pointing them, or blurting, etc. Idk what else there is tbh. ACTIVE RECALL is also great, the way u do it is by explaining a topic to ur family/pets like they're 5-year-olds.
6) I did consider getting an IPAD, but I didn't, idk why. I wrote on paper, and it was such a hassle trying to file them, so yeah, bring an iPad or a laptop, it helps with organisation a LOT.
7) CGP ofc is the goat, YouTube, Seneca, PMT, etc
8)TBH I might have to retake chem bc I'm doing so bad in it (hopefully I'm not but) I would fs just would understand the topics a lot more, do a lot more practice and not procrastinate until the day b4 the exams to revise.
9) Good luck with A-levels, and please don't stress rn, go enjoy ur holiday!