lil N
Chemistry Unit 3 is pre chill, but Unit 4 requires you to be on the ball and a lot of memorisation. Practice questions and drawing diagrams out multiple times should help
Physics, unit 3 calculations go from linear to quadratic and it becomes slightly more complex to apply the right equations to the questions. Unit 4 really requires a lot more understanding (except topic 3, you can kinda memorise some things) than Units 1&2.
U3&4 Methods is just building upon Unit 1&2 methods so if you get the basics, you should be right.
I didn't do spesh or bio so I hope someone will answer that one.
Feel free to ask more questions,
-jinx_58