AQA A-Level Politics

Hi,
My teacher is really bad at teaching US Politics for A-Level. Can anyone help me give me some advice as I have realised I basically have to LEARN (not even revise...LEARN) the whole of the US part of AQA A-Level Politics and I don't know what to do and where to start.
If anyone got an A* or A please tell me how you did it because I always get stuck on analysis and don't know how to access the high bands.
I'm honestly so screwed so any advice would be really appreciated!!!