The generation effect is a robust memory phenomenon in which actively producing material during encoding acts to improve later memory performance.
This phenomenon has been first cited in 1978 on the Journal of Verbal Learning and Verbal Behavior. Scientists described it as the phenomenon where information is better remembered if it is actively created from one’s own mind rather than simply read in a passive way.
Thus, the best way to understand a topic is not to read about it, but write about it.
Trying to explaining something to someone else help yourself to connect the dots and to memorize far better than the passive act of reading.