Took one of my color-me-in pics and went to town with shading practice, trying out some techniques I learned online. There really is no shortage of advice videos out there, but you have to actually do as they say rather than just watch.

Otherwise, the mind forgets about it quite quickly. Learn it once and let it sit without study. It'll be gone in the morning.

The body, however, doesn't forget. Not if you practice. Repetition. There are videos for what and how to practice as well. Seek those out in-between guide vids. This skill takes a while; don't lose heart.

In this kid's case, neither his mind nor his body are forgetting this experience anytime soon.