Are you in year 12?
I used a mix of resources. I will happily link some of them if you want as I have several saved on my google docs somewhere!! With OCR, I found it so hard to find resources due to it mainly being AQA resources. When I was having a long revision day, I would make flashcards on quizlet but I would do these as I went along with the course because it makes it so much easier when it came to exam days and mocks. I would also do past papers and sometimes these would be by topic e.g cell membranes and sometimes I would just do a past paper from like 2017. Make physics and maths tutor your best friend (promise it's worth it!). Around December, I had a goal of trying to do every past paper, even some of the old spec ones and trying to redo them to get higher but obviously due to corona happening I stopped revising after March. I made this tracker on google docs and would record what I would get on papers. I would defo say start with your hardest topic first because as much as we love the ultrastructure topic, the plant transport topic isn't about to go anywhere!! On a lazy day or if I just didn't understand a certain process I would watch videos on it. Most of the time it would be OCR specific videos like MrBioTom, BioRach and someone called Ryan Toal. However, I would also watch crash course videos.