LOL NERD DONT START GOING ON TSR YET, THEY WILL RUIN YOU
Other than that the only thing I can advise to you that works is to read ahead on stuff, when I was in year 10 I read my entire physics textbook and ever since then classes became easy and I got consistent 90% in every exam. It's not because you know the material that it helps, but because you learn to learn independently and you understand things far better that way.
BUT NOTE I DID NOT GO ON TSR AND I WAS NOT EXCITED ABOUT MY COURSES AND I WAS NOT A NERD, AND NEITHER SHOULD YOU BE ONE! GO HANG OUT IN THE PARK!