It is important to be able to evaluate whether things “work” and why, and equally important to be able to “hear” what others have to say about your work.
Be able to describe what you see and hear.
Make a judgment about what you see/hear. “I like it” is not enough.
In general, be positive and constructive, but don’t hold back negative criticism. It’s important to give honest feedback. That doesn’t mean you can’t be tactful, though.
Also, consider the work in the context of the maker’s intention.
Show your work and listen. Don’t jump right into defending or explaining it.
When people talk about your work, pay attention. Don’t be defensive.
Take notes yourself, or ask a fellow student to take notes for you. It can be hard to hear what people have to say about your work, but getting feedback is an invaluable help in the process of creation. Come back to the written comments after a few days, when you have a little distance on the work and the experience of the critique.