How do you go about it?

I cannot speak as an educator. As a student the "ah ha" moment for me was when the professor explained to me that nurses do not diagnose disease, we diagnose reactions to to disease and environment. That whole weight of not diagnosing he disease seemed to clear it right up for me. I was able to think of the disease in terms of pathology and what I would "expect" to see with it. Don't know if that helps.

Great observation. I've noticed this does help a subset of students make progress.

LOL - I didn't clue into this until I was in grad school. That was when I finally internalized what nursing was all about. I wish that they had clarified this in my BSN program.

I remember an instructor telling us that the diagnosis had to relate to something the nurse could do something about. For instance, I cannot presecribe treatment for diabetes. But I can teach self care.

For sure. You cannot "diagnose" anything that is outside your scope of practice. But sometimes (IMO) there are diagnoses that you'll make about which no one can do anything. Still... it's a part of understanding the whole patient.