1. Get off this website.
Don't get off this website if you have questions to ask or want to access lots of notes and stuff

Use the apps Heidi mentioned above to block all the bad ones, keep ones like ATAR Notes around to drop in for quick questions, keep any cool videos on content you find unlocked, etc

PS - I
LOVE the Pomodoro Technique: Lots of short intervals with quick breaks in between as Heidi described works absolute wonders for maintaining concentration.
PPS - Try studying for different subjects in intervals!! Like, an hour on Physics, an hour on General Math, an hour on English, etc. It keeps your brain doing new stuff and keeps you from getting bogged down on one specific style of thinking. Your brain works best when you continually mix it up (hard if you are doing practice papers or what have you, or trying to chug out a big assignment, but
perfect for keeping you focused on writing study notes or doing weekly revision of concepts, etc
