The videos, sites and past papers that actually help, sorted by subject. Everything here is free. YouTube links may be blocked on some school networks, so watch those at home.
Watch, then test. After a video, close it and write down or say what you remember. Then check. Watching alone feels productive but doesn't stick.
Past papers are king. Once a topic is learned, do exam questions on it and mark them with the mark scheme. Read the examiner report to see where people lose marks.
Little and often. 25 minutes of focus and a 5-minute break beats a 3-hour cram. Use the timer in the header.