See how KJG draw the external shape or contour, then he draws inside that.

Doing things that way, you can even use the same shape but draw different things inside, such as the fingers on the right of the picture, where he basically drew the same shape, but the fingers are in different angles.

It's also much easier to memorize the shapes if you keep it simple, since shape conveys information, and less information = easier to memorize.

I hope that this is useful for some anons, but if someone wants to know more, see Kim Jung Gi videos and listen to what he says, also Krenz videos on Youtube are very insightful on this topic.