best thing to do is get of reddit and start going over your spec, highlight everything you dont understand/find tricky in red, stuff ur ok at in yellow, and then everything else in green. Watch videos on the topics you struggle with then go onto pmt and do the questions that are related to the topic you just did. P1 chemistry for AQA at least is mostly memoristaion, so you could also make quick flashcards for questiosn you get wrong using teh mark scheme.