science- CGP guides are a lifesaver, helped me to get 3 A stars in science, however must do loads of past papers too, the same questions always appear e.g carbon monoxide in chem, fish farm in bio, magnets in physics. these will help you get familiar with the mark scheme and understand how weird some of the answers are.Maths - i got a 9 and past papers were really important, as well as seeking teaching help for topics you don't understandTry and do around 30 past papers for each science and depending how good you are at maths, more or less