For most of the posters that we had, I found out that they commonly analyzed the color. I think red was prevalent as it symbolizes communism.
The Chinese people seemed happy, and the overall poster was trying to convey a positive message about the revolution.
Moreover, most of the poster used appeals to ethos, which relies on the credibility of the poster.
As the poster includes lots of figure, I could spot that symbolism was one of the main techniques too.
Lastly, most of our classmates analyzed the words, including font size and word choice.