One of these is the practice of "testing." Particularly in a professional business environment (though it is often true in colleges and universities), tests or quizzes aren't the most effective means of assessing learning and performance. But psychological research demonstrates that the harder one works to retrieve information, the more accessible that information becomes--especially over longer periods of time. I've been thinking about this recently as I've become accustomed to taking directions from a GPS. If I drive somewhere new under the precise and soothing direction of the robot in my phone, I nearly always arrive at the correct place, on time, without any mistakes. But, when I try to drive back to that place without a GPS (testing my memory), I remember very little about how to get there. Conversely, if I have to drive somewhere new without such guidance, and use more manual and laborious means--writing down or printing out directions, then reading over them, trying to remember them as I drive, stopping and reading them again after I've missed a turn, etc.--I have a much clearer memory of the route the next time I try it unaided. The lesson here is that while the GPS might accomplish the task of getting you to a destination, it isn't as effective at helping you learn how to get there.
Let's go one step further: if you have no specific directions to a place, but only a vague set of reference points--say, the east side of town, near a certain building, red door with a big tree in the yard--and you wander around, lost, trying and attempting different routes before you find it, what you have learned is even more substantial. In such a scenario one creates a memory not only of a route or set of precise moves in space, but a much larger mental map in which to situate the memory of the location.
In the same way, how might we "test" learners as a means of reinforcing memory, which isn't experienced like an exam (which can create anxiety, or darken the mood, and can impede learning)? One method many of us use is called "pre-testing," in which learners are asked to retrieve information that has not yet been introduced (like trying to find a friend's house without full directions). Pre-testing creates a kind of mental map, building a field in the brain on which the information will eventually be placed, and accessed more easily later. Working hard to find information that isn't there provides traction--we might even say sets waypoints--in the brain so that when the information is eventually learned, it already has a place to go, and we have already done the work of learning where to find it.