There's a wealth of material online about Anki, but if you'd like to hear it from me, here goes...
Anki's a spaced repetition flashcard app that's an incredibly powerful tool for remembering information. It lends itself particularly well to languages and science subjects such as Biology and Chemistry, but also to subjects like Economics and Psychology.
Spaced repetition is a technique whereby you're exposed to information at gradually increasing intervals. The idea is that each time you test yourself on the same information, you'll retain it for longer. This leads to better recall and improved exam performance.
Anki can be described as flashcards on steroids. It's not just text you can put on them- images, videos, sound clips are among the things that could populate your flashcards. The applications are damn well near endless! You can also sync your progress across multiple devices (for example, a phone and a laptop). This has really helped.
Every time you flip a virtual flashcard, you'll be presented with four options- Easy, Good, Hard and Again. The idea is that you test yourself, and, after seeing the correct answer, rate how hard you found it. It's really important to be honest! The harder you've rated it, the sooner you'll be seeing the card again. This allows you to focus on the stuff you're struggling at, rather than the stuff you're already really good at and don't need much reminding on. Over the long run, this saves so much time.
Anki also has an algorithm that works out when you're about to forget a card, and gives it to you just as you're about to forget it. This helps fight that 'forgetting curve'- ensuring all-important recall is always flawless.
In what might be viewed as a downside for some, Anki's at it's most effective when used by someone over a long period of time who is committed to that lifestyle- who will endeavor every day to complete all the assigned cards. This is hard! But in the long run, it really does save a lot of time and pain. That said, even if you don't have so much time, it's still worth using, for Anki is also a phenomenal cramming tool.
Even before starting this website, I've given my decks to people across all 4 subjects and have just watched them absolutely take off. People have gone from Bs to being on the cusp of an A* in mere weeks. Or better. That said, A-Levels aren't all about recall- and your revision should reflect this. Equally undoubtedly, though, a large chunk of them are- and for that there is no better tool. And, I might add, it seems that most of the time it's not understanding that's the issue holding most students back- but recall.
AW