A level resits need ADVICE

I got an A in Biology this year and the main thing I did to revise was exam questions. I'd maybe do a topic test first (available on sites like PMT etc.) to gauge my level of understanding. If my understanding wasn't great, I'd either go over the topic through using the textbook, YouTube, or uplearn, and then I'd do a bunch more exam questions to test my understanding. I would recommend using the site 'cognito' for chem/ bio exams questions (unfortunately it is a subscription you have to pay, but it isn't too extortionate - around £10 a month) because they have these large banks of questions per topics (they had 100-200 questions for some bio topics). But, I would specifically aim for a certain percentage in the topic tests - I counted an A as 65% (I believe an A was actually around 63% but I wanted to overshoot a little bit) and an A* at around 73%, according to last year's grade boundaries. I would then aim for at least 65% in every single topic test I did.
Because, towards the end of the year, I wasn't necessarily learning anything new, I didn't necessarily find doing so many exam questions too mentally exhausting so there wasn't a set amount of time I'd do it - I just aimed to get through all of the topics as much as possible.
But I'm sure someone else will write a more detailed approach. I'm an extremely disorganized person so I never had a consistent schedule/ set of time I'd revise for my subjects. I did also get pretty burnt out right before my exams, so not many tips regarding avoiding that ;(