>>1082654>>1079984>standard overall realism with slight indication of hatching (subtle hatching for rendering, very carefully crafted)so pay attention to all aspects, like the usual form, value, and stroke direction. study from life mostly to achieve this technique
>>1080072>soft renderingmuch simpler technique and not as demanding. just imitate a photo's rendering to a high degree without too much detail and outline it heavily. you don't have to have as much knowledge of form or anatomy as long as your lighting allows for complimentary values to create more indicative structure, as opposed to YOU having to indicate the structure because of the angle being not very forgiving, etc
>>1080100>directional hatchingthis one is one of my favorite techniques since it's so damn subtle. it's hatched, but the direction in which you hatch dictates the form of the structure, AS WELL, as the hatching being very tightly knit, with a wider/flat hard line, going lighter and darker per value. it's one of the closest hatching techniques to painting since the line are so close together AND flat that it looks like even wider strokes than it's made out to be. very strong stroke economy knowledge for this technique. don't waste lines and give yourself some nice lighting with lots of midtones to really make this look it's best.
hope that breakdown helped!