I am a PhD student and I have been contacted today by some other PhD student with a very odd request. He is from a different university in a different country and I don't know him at all. He is asking me to review his own paper before submitting it to some journal. Is this a common thing to ask? What is the best response in this case?
I'm not surprised to hear this. I often encourage my students to reach out to others working in their specific field. Do it if you have the time, interest, and expertise. Ignore it if you don't. Don't think there's more to it than that.