Got a B (a few marks off an A) last year in Chemistry and resitting this year, pretty much started revising around a week ago again. Only things I would really say is practice a lot of calculation questions, things that you simply just have to remember such as certain results or organic synthesis routes I would just sit down and learn it off by heart. Oh and I would also suggest not neglecting practicals (my mistake last year).If you have any questions pm me ill happily answer.