The design methods of the billboard with roasted cold noodles and stinky tofu include selecting appropriate colors and adding gourmet elements.

1. Select appropriate colors: you can choose bright and bright colors, such as red, yellow and green. These colors can attract people's attention and make billboards more conspicuous.

2. Add food elements: You can add some food elements to billboards, such as pictures or patterns of roasted cold noodles and stinky tofu, so that people can think of these foods at a glance.