What cognitive science research says actually works.
Testing yourself on material is more effective for long-term retention than re-reading or re-studying. This is one of the most replicated findings in learning science. Flashcards, practice tests, and self-quizzing are not just assessment tools — they are among the most effective learning tools available.
Reviewing material at increasing intervals — before you fully forget it — is dramatically more efficient than massed practice (cramming). Software tools like Anki implement spaced repetition algorithms that optimise review timing. For any content that requires long-term retention, spaced repetition is the state of the art.
Blocked practice (all problems of type A, then all of type B) feels more productive but produces worse long-term retention. Interleaved practice (mixing types A, B, C randomly) feels harder but produces better results. The desirable difficulty is real.