When I started learning Korean from an app, I passively consumed the words as though I’m playing a guessing game. This helped initially as I learn words at a very fast pace and feel good about it. Later on, I realized that I’m retaining less and less of those words and became just a “word collector” without truly retaining what I’ve learnt.
So I went back to basics and started just writing down what I learnt. I started seeing patterns and grouped similar things together. The grouping exercise helped to link ideas so that I can remember them better. The physical nature of writing words down also somehow imprinted something in the brain that makes me remember easier.
After several weeks of doing this, my son started learning with me as well. So I created a set of cards on the Korean alphabets just for him. :)