Think of the difference this way:
In writing essays, you do the talking.
In writing news, you let your sources do the talking.
Apply this test to any story you are ready to hand in: Is there any sentence, other than a sentence that relates a verifiable fact (Christmas falls on Dec. 25) or reports an observation (Smith was wearing a Duke sweatshirt), that is not attributed to a source?
I find that some students who are otherwise careful with attribution can't resist the temptation to write an essay-like conclusion to a story, especially a profile, and therefore end on a note, not only of failed attribution, but also of editorializing.
It's great to have a good quote or anecdote with which to conclude a profile or other kind of feature story. But it's not necessary for this course. You can simply stop.
Consider this example, the final sentence of a putative profile of Professor John Paulmann that has as its theme John's long-time interest in radio.
1) Paulmann's interest in radio has given him many pleasant hours during the last three decades.
2) "My interest in radio," said Paulmann, "has given me many pleasant hours during the last three decades."
1) is the essay-like conclusion mentioned above.
2) is an attributed direct quote that also has the virtue of leaving the reader with a closing summary of the story's theme.