Anki is a free and open-source flashcard program using spaced repetition, a technique from cognitive science for memorization. The name comes from the Japanese word for "memorization". Wikipedia 
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It is for memorization, not learning in general. If you need to master a concept from scratch, or learn a procedure, or problem solve, Anki is not your go-to tool. Article
The ideal flash card takes no more than two seconds to understand what’s being asked, and no more than five seconds more to answer it.
I don't have anything special here, but I have got content on Meta-cognition that might be useful.
The biggest power users of Anki are people in Medical School. The biggest producers of decks is called AnKing. Website
AnKing has a video that describes their format for creating decks. Youtube
I've made some notes on Using Cloze Deletion Cards that should be helpful for figuring out how best to learn facts using this card type.
There are great tutorials from Glutanimate on how to study more effectively using Anki. Youtube
There are great resources from The Accelerated Learning Cannon to help speed up your learning. Youtube
There's an essay on the Ankification of a topic to get a deeper understanding. "[some] cards written along the way have the flavor of exhaust, bad cards that seem to be necessary to get to good cards". "grandmaster chess players... [are] not remembering the individual moves – they’re remembering the ideas those games express, in terms of larger patterns. Article
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