Many people find it hard to revise effectively because there isn't just one technique that suits everyone; what works for you might not work for your friend. Finding out what does work for you often takes time and can be a process of trial and error, which can be frustrating at times. 

So where do you start? Experts suggest that you use a combination of different techniques that work for you, that combine active recall with spaced repetition before consolidating this with examination papers. This does require a little planning, so starting early and following a revision timetable is a great place to start. 

From there, you can experiment with different active recall techniques until you find what works for you.