1, good at choosing and comparing. This is a very important problem in the process of sketching. The object to be painted, which places are important and which places are secondary; Where to emphasize and where to omit; What helps to shape the image and what will damage it. This should be done after careful observation. Due to the short sketch time, it is impossible to draw all parts of the object in detail.

2. Generally, painters focus on the key parts first. What are the key parts? The whole posture, face and gestures are important places for people's expressions. As for the dress, just draw the key turning point of the dress pattern, and the minor part can be omitted. If you draw a mass scene, it is important to draw the external form and action characteristics of the characters and the relationship between people. Draw a dance action. If we only pay attention to people's five senses, the dance movements will have changed a long time ago, so we can't continue painting.

3. In fact, the whole process of sketching is the process of correcting mistakes in comparison. Such as seeking its accuracy, height comparison, left-right comparison, front-back comparison, length comparison. In addition, there are the strength, weight, reality and angle of lines, which should be constantly compared to accurately show the object. In fact, sketch is also a practical process from perceptual knowledge to rational knowledge and then to perceptual knowledge.