1. First, determine whether the city concept you want to express is a city with a sense of science and technology in the future or a city with a classical style. The atmosphere and architectural style of the city can affect the overall picture.

2. Secondly, draw the background according to the atmosphere and style of the city. For example, the future science and technology city can draw high-rise buildings, suspended vehicles, high-speed passages and so on. And classical cities can draw old buildings, narrow streets, etc.

3. Then draw the streets and buildings, determine the location of the main streets according to the perspective, and draw the streets with straight lines and perspective.

4. Then add details, such as windows and billboards, to enrich the picture.

5. Then render and color, using colors suitable for the urban atmosphere, such as blue-gray for the cool tone of the future science and technology city and brown-yellow for the warm tone of the classical style city.

6. Finally, add special effects, such as fuzzy perspective and night scene effect, to make the picture more attractive.