Q: How to differentiate two types of post?

I am new to UX design and I am currently developing a design prototype for our project. Our project sort of a social media + shopping website. For our website, there are two types of posts: shopping offers and order requests. I have conducted a usability test already and some of the participants said that it was a little bit hard to differentiate the two types of posts because they look similar. How can I provide a more obvious differentiation for these two types of posts? Any suggestions would be highly appreciated!