What are the requirements and methods of sketch?

Is to grasp the structural characteristics of things. On the basis of in-depth observation of objects, complex natural images are selected to make them more concentrated and generalized. And accurately capture the instantaneous changes of objects and images, and strive to be regular and lifelike. The important part should be described in depth. There should also be written records, indicating the time, place, environment, name, characteristics, etc.

The methods of sketching in painting are sketching, sketching and coloring, ink painting, sketching, write slowly and dictation.