/ic/ - Artwork/Critique

I'm used to doing precise, linear sketches but I'm trying to get into more expressive, painterly renders. But I'm having trouble turning the former into the latter because I feel like I have to sacrifice the precision of the sketch for the sake of painterly strokes and effects, which feels like a step down. Pic related is an example of how I'd like to be able to paint. Any tips for this? Is it the tools I'm using, or is it just me?

Please, tell me what knowledge is required to draw something similar.
To me this is perfection, this is art, this is what inspires me and millions of people.
I look at this image and become jealous, I want to achieve the same level of skill.
I'll do everything.