How can I emulate strokes on the picture above?

There are a few brushes "presets" that emulates charcoal at some degree, by modifying the presets settings even further you can achieve some "angle" with the size variation, the pressure of your pen would give a different amount of opacity, for a even more natural "grain" you can turn on "rotation" of the brush tip. Here I made a quick test of the mentioned brushes.

https://drive.google.com/file/d/0B-cDWU ... sp=sharing

Hope it helps to a least give you an idea of the possibilities : )

Quiralta wrote:There are a few brushes "presets" that emulates charcoal at some degree, by modifying the presets settings even further you can achieve some "angle" with the size variation, the pressure of your pen would give a different amount of opacity, for a even more natural "grain" you can turn on "rotation" of the brush tip. Here I made a quick test of the mentioned brushes.

https://drive.google.com/file/d/0B-cDWU ... sp=sharing

Hope it helps to a least give you an idea of the possibilities : )

Pencil texture was the closest among what you recommended. I want to feel the texture of the picture below, but pencil texture can't mimic the texture.

The actual tip of the brushes can be changed to something closer to what you are looking for, there are the default ones but you can also download other brush sets (some that are here https://docs.krita.org/Resources ) or make your own brush or only the tip. I personally like to make the tips rotate for a more natural and spontaneous texture result, but there are many settings that can be tweak, is hard to tell (since many tablets/pen behave differently) an exact approach.

For that type of picture I would use the "air brush" and change the tip to something like "concrete", then use it alternating erase blending mode as needed for the highlights. That would be one of many ways to approach it though. Raghukamath's has a brush with very similar grain. you should give it a try.