If you think, the brain is the only part of our body that can remember then all we have to do is read book about arts, then we can go directly and proceed painting. But that's not the case, often taken for granted was our muscles capabilities to retain or memorize activities.
Observation needs practice too. At first glance we might miss the different grains and tones but constant looking will lead us to various shades and hues (plus eye strain too). Learn or discover to see things as they really are and not what you think they are.
Matters are a combination of substances. If we look deeper into the material composition of things it would be easier to translate them into reality....
Two things must take place; the substance of your model and the properties of your medium. See how the pigment behaves; like to what extant it will move or the limitations it displays. In every action there's an equal reaction and that every color has an individual characteristic --
Don't be afraid to experiment, and even if you don't get what you expect you'll still be discovering something...our muscle (pulse) will still develop because constant activities forms a habit. Teaching our hand to paint...will SURELY gain what it has invested.