I watch a lot of painting demos these days, looking for Procreate tips. Digital painting may have a similar perceptive core, but the execution is different. Few videos are as serene and revealing as this one of Studio Ghibli background artist Osamu Masuyama painting a sky and landscape.
This is one of the traditional ways art is taught in school. You watch a master work up a painting or drawing, and you try to do what they do on your own. Most of art, any art, is practice, I believe. There are techniques that will save you time, and specific exercises that can give you facility with the work, but time and effort is the biggest factor in anyone’s level of ability. Talent only goes so far.