Characterization

Aura

Auras can show killing intent or good will, etc.
Auras are not diegetic.

from Solo Leveling Chapter 21
(killing intent)
[from Solo Leveling Chapter 21]

Emphasis

No Background

You only need to draw the background to establish the setting or show a wide shot. Otherwise, it's common to just draw the foreground (characters or objects).

The empty background can be a flat color.
Fades or patterns can be used to add tone or characterization.

Zoom In

Tightly zoom in on the one part of the scene the reader should focus on.

I usually want to draw full scenes, but that is often the wrong choice.

from Solo Leveling Chapter 20
(this man is scheming)
[from Solo Leveling Chapter 20]

from Solo Leveling Chapter 20
(characters are traveling)
[from Solo Leveling Chapter 20]

Solid Silhouettes

Characters are shown as solid silhouettes, instead of detailed. Either their identity is not known yet, or the important things is that they have arrived.

from Solo Leveling Chapter 22
[from Solo Leveling Chapter 22]

Action

Dissipating Limbs

Elongate the limb until it dissipates in motion marks to show very very fast action.

from Solo Leveling Chapter 22
(a very very fast leap)
[from Solo Leveling Chapter 22]

In The Past

Gray Tones

Reuse previous panels, but in grayed out tones, to show a character remembering the past.