To attempt to put it to words, you first want to find a canvas texture that’s the same or higher resolution than what you’re working at. I work at 72dpi- industry standard for web graphics- for sprite edits. Take that image in whatever program you use and put it in grayscale, then adjust it to a neutral value, i.e, “middle gray”. Turn it into a multiply layer at ~5-20% opacity, (it will depend hugely on the value of what you put it over.) Pastels and whites will require some additional fiddling but that’s what I find works for most clothes and hair for me.
To put the texture onto the sprite I’m working on, I take the canvas texture I just made and convert it to a clipping layer, and then apply it to only the hair and clothes, omitting the skin.
Edit: I reffered to the sprite style as being Komatsuzaki's own several times in this. Just wanted to clarify he doesn't make all the sprites, there's a team of artists under him that do. (hence the inconsistencies between canon sprites)