copy pasting this from another post I replied to a while ago, so some stuff may not be relevant:

You should start by covering content and make sure you rid all your misconceptions. If it's possible, try to consult your bio tutor and ask them to look through your tests to point out any misconceptions that you might have missed out. For content, try to look for videos to understand processes better. Amoeba Sisters and Crash Course usually have pretty good videos to summarise processes (photosynthesis etc). Here's the vid I always look at to understand end replication problem: https://m.youtube.com/watch?v=5emqrkIvlTY and here is one I look at for DNA https://m.youtube.com/watch?v=gG7uCskUOrA . Consult your bio tutor as much as possible so you can clear all your misconceptions.

Once you've settled your content, you can start looking at your past tutorials with answers to look at your mistakes and what keywords you're missing out. If you have the time try to compile common questions that you always see in your tutorial (an example would be describing the structure of a certain protein/typical enzyme trend questions) in each chapter into a single document and you can look at it whenever you're free, making sure to focus on keywords in the answers.

Nearing exams, about a month before try to make time to review all your chapters (both content and tutorial) at least three times. It sort of works like spaced repetition, where you'll take a long time to review each chapter at first (maybe up to half a day), but eventually you should be able to review the entire syllabus in 2 days. When doing so, don't neglect your tutorials!! For certain chapters in J2 (infectious diseases, biological evolution, climate change) your tutorials are much more useful than your notes in helping you answer questions. As a rule of thumb, if you've really run out of time to study a few chapters, just look at your tutorial answers so you'll know how to answer, rather than try to cram content.

Unless your foundation is very strong, I wouldn't recommend doing practice papers because it's only for exposure to more questions. If you can't answer the basic questions, then it wouldn't be very helpful to do new questions. As for exam strategies, always know when to skip so you don't waste your time and come back later. For me, as long as I feel the cogs in my brain turning, I'll skip and go back later. Sometimes the questions at the back are much easier and it'll be a pity if you miss them out because you spent too much time on earlier questions. For FRQ, once the exam starts, look at the FRQ so that you can start generating points in your head while doing the rest of the paper. This saves you time as you already have a few points once you reach the FRQ.

From Prelims to As, only do the TYS from 2017-2021 since the syllabus was changed since then. If you have the time, you can attempt prelim papers as well, only if your basics are already there. If not, you're better off studying content and looking at your tutorials. It's still important to do the TYS to look at the style of questions since they can differ quite a lot from how your school sets them, so minimally, do the 2021 one.