/ic/ - Artwork/Critique

Okay so how do I obtain a color harmony like pic related, I am this close to achieving my own "artstyle" but I am always end stuck when I have to select my palette. All I can get from these works is that one color is always on the higher saturation side among a bunch of grays, and all of them have a warmer tone. But how do I know I am doing the right color choices? I know the answer is gonna be practice, but still is there a "shortcut" or key to achieving this specific approach to coloring? I am currently reading Quiller's Color theory book and it mostly talks about color wheel and scheme types so far.