Anki is an awesome app that uses spaced repetition learning to memorize and learn things efficiently.
The reason I am not currently using it is because I find the philosophy of
Knowing something is knowing where it is written down. much more effective than memorizing things. And I am pretty fast on the computer already so looking something up is 'nearly' as fast as retrieving something from memory. Also I believe that doing something that you want to get good at a lot of times is the only real way to learn and master anything. That said, Anki is pretty great for learning vocabulary for a language as that is something where memorization and 'knowing' some thing is actually important. But even then being immersed in the environment where you try to speak the language is much more effective.
A language isn’t something you learn so much as something you join.
Review all cards every day, not just one topic. Ensure that you're not hitting the "Review limit" on a deck.
Use tags: Tag all cards that are more likely to appear on your exam and review them more often.
Use Lapses: if you fail a card n times, then let it be suspended and work on rewording it.
Reduce the amount of time spend on cards. If you do not have near-instant recall, mark it as "Again" and spend more time learning.
Image Occlusion Enhanced - Lets you create cards that hide parts of an image to test your knowledge of that hidden information.
Anki works due to the exponential decay of memory - The better you know a card, the less often that it'll be shown to you.