>>21903986It's pretty easy once you learn how. All you need is an image editing software with layers and the ability to transparently lock layers.
Place your flat colors down first. Each color should be in its own layer, i.e. skin, shirt, shoes, leggings, undershirt, hat, hair, gloves, etc. Make sure they the colors on top aren't overlapping the ones beneath--if they are, go back and erase along the edges.
Once you've got your flat colors done, now comes the daunting task of shading. There's a lot of different types of shading you can do, but the two people mainly use is cel shading (where the shadows are hard and are on their own layers for the most part) and soft shading (where the shading is more rounded out with gradients and subtle shades). Sugimori's art is mostly cel shaded with a bit of softness and textures mixed in. Now, shading is really obnoxious if you don't know how to light source. The exact location of the shading will depend on where your light source(s) is. If you're having trouble, try thinking about where the light would not touch or look at real life objects and think about the shading.
Hard to explain, but I can link you to a thousand different tutorials on coloring if you'd like.
