Memory follows a decay curve, spaced repetition is a technique that improves memory

Researchers have found that memory follows a decay curve: new concepts need to be reinforced regularly, but the longer you’ve known a concept, the less regularly you need to review it to maintain accurate recall. 

Spaced repetition and reinforcement is a memorization technique that helps you systematically review important concepts and information on a regular basis. Ideas that are difficult to remember are reviewed often, while easier and older concepts are reviewed less often. Flash card software programs like Anki,1 SuperMemo,2 and Smartr3 make spaced repetition and reinforcement very simple. Spaced repetition systems rely on a “flash card” model of review, and you have to create the flash cards yourself. By creating flash cards as you’re deconstructing the skill, you’re killing two birds with one stone. 

Once you’ve created your flash cards, it only takes a few minutes each day to review them. By systematizing the review process and tracking recall, these systems can help you learn new ideas, techniques, and processes in record time. If you review the decks consistently, you’ll memorize necessary concepts and ideas extremely quickly.

Create scaffolds and checklists. 

Many skills involve some sort of routine: setting up, preparing, maintaining, putting away, et cetera. Creating a simple system is the best way to ensure these important elements happen with as little additional effort as possible. Checklists are handy for remembering things that must be done every time you practice. They’re a way to systematize the process, which frees your attention to focus on more important matters. Scaffolds are structures that ensure you approach the skill the same way every time. Think of the basketball player who establishes a pre–free throw routine. Wipe hands on pants, loosen the shoulders, catch the ball from the ref, bounce three times, pause for three seconds, and shoot. That’s a scaffold.

The First 20 Hours: How to Learn Anything . . . Fast! by Josh Kaufman