I know nothing about Spaced Repetition

• How To Remember Anything Forever-ish is my goto reccommendation. It's interactive and adorably drawn.

• Augmenting Long-term Memory by Michael Niesen. A classic essay, covers the same ideas with a bit more seriousness.

How do I write good flashcards

• Soren Bjornstad's post describes good flashcard design through broad rules,

• Michael Nieslsen's post follows through a linear algebra proof in depth.

• Andy Matuschak's post goes a step further, guiding the reader through the steps of writing flashcards interactively.