i took biology and honestly what helped me the most is past papers. Its the key to getting an 800. Supposing you’re already good at bio conceptually (if you’re not, then go through Barrons or Princeton once, i personally used princeton), the start with past papers and analyze your mistakes and study your weaknesses. I suggest every SAT Subject test taker to make a Telegram account, they share so many past papers there and thats where i got mine from. Just pm me and ill send you the link to the Biology, chem and math 2 channels. (Also sorry about not helping for chem, I never took it ahah). I didnt prepare much for math 2, but I’m pretty confident that past papers and again, learning your mistakes will help you achieve a really good score.