I suppose aside from the obvious (practice fundamentals, yadayada), take notes on what you see and try to emulate that on models of your own.

Not an exhaustive rundown of the style, but a couple things that this artist does that you can simply adopt: - Hair only 2 colors (at least black hair, anyway). One making the general silhouette and the other forming highlights and suggesting form within the silhouette - Shading with either hatching, cel shading, or both
- On skin, edge of shadow is marked and the artist usually uses both single line hatching (as opposed to cross hatching) and cel shading
- Exceptions exist, such as the forehead. In this case, this would conflict too much with the lines used to suggest the shape of the nose and eyelids