Out of your subjects I only did Biology and Maths so can only comment on those really but anyway here goes:
Biology- little and often throughout the year, really listen and pay attention in class, take an interest in your practicals, briefly take a look at the pages in the textbook for your lesson before you have the lesson and read/take notes after your lesson as well. The key for biology really is repetition repetition. Try and find old past papers to do throughout the year and save the newer exam papers for a month before your exam. Do each exam paper at least twice. Read examiners reports to get an understanding of how you should word your answers and areas students commonly make mistakes in as these are likelier to come up. Learn mark schemes as well. Learn the specification points. What I found really useful was to get loads of flash cards and put a specification point on one side and the answer to that point on the other side. The answer can come from your textbook or mark scheme answers as sometimes exam questions are literally directly from the specification point. Try and max out on your coursework as you have a bit more control over it and it will mean even if an exam goes badly, you've got some insurance to fall back on. Go to drop in session held by your school st lunch times to ask any questions you have about material you don't understand.
Maths: simple really, past papers, past papers, past papers. Go see your teacher at lunch times or get someone who understands a concept to explain it to you if you don't get it. Watch YouTube videos if you don't get a concept. Once you watch a video or read the textbook just do loads and loads of questions until you feel really comfortable with that concept. Do all the Solomon papers as well because they're harder so you will be prepared for the worst. When doing past papers, literally do them dating back from like 2002 as well