What exactly makes a piece creative nonfiction?

I took the Creative Nonfiction track in earning my English degree. Many of the students focused on memoir (myself included), though we also wrote magazine-style articles and profile pieces.

In my experience, there was always an "authorial presence" in creative nonfiction stories. That's a given in memoir, but even when we were writing about local events or personalities, there was always a sense of seeing things through our lens. This is in contrast to pure journalism, which usually aims to get the max amount of information across with minimal personal style.

Whether or not you incorporate statistics into your creative nonfiction story really depends on the media to which you are submitting. Same goes for including a persuasive argument. The creative nonfiction pieces that I've read were usually very subtle with these elements, if they were included at all. The focus was more on the story and voice than raw facts.

For reference, my courses' required reading included pieces by Jo Ann Beard, Joan Didion, and David Foster Wallace. While Beard and Didion lean more towards personal essays, Wallace worked in a lot of relevant numbers, etc. Check out essays from Beard's "The Boys Of My Youth" or Wallace's "Consider the Lobster" for two very different examples of creative nonfiction.

Hope that helps!

Maybe this is a bit of a flip answer, but Carrie Badshaw in Sex and the City writers creative non-fiction.

Anytime you write a piece of narrative where you as a person, or where some other person, is central you're really writing creative non-fiction. That can be a memoir, a column, an essay, and so on.

Or, put it another way, make a distinction between subjective writing and objective writing. If you're writing a subjective piece, you will be landing in creative non-fiction. Your experience will matter. If you write objectively, you will most likely not be writing creative non-fiction.

Memoirs and autobigoraphy are two common examples of this type of fiction. I think a difference between CNF and a traditional non-fiction piece is the focus. In non-fiction, you focus on getting the facts across to the reader is the easiest way for them to understand it. In CNF, the focus is on truth and on story.

There's an anthology of works called The Best American Essays that comes out every year that I've heard is very good that you might want to check out from a library sometime to get a feel for the genre.

It's a true story that uses fictional techniques. In other words, it reads like fiction, but it's all true.

James has the essence of it. Some creative non-fiction books I've enjoyed include Eat, Pray, Love and Julie and Julia. Many creative non-fiction pieces (short and long) are based on travel experiences or are memoirs. If the story is true but it's told in the style of a novel or short-story, it's creative non-fiction.

I just finished Nasty, Brutish and Long by Ira Rosofsky. I think it must be a great example of creative non-fiction. It was an engaging page-turner, and I learned so much from it. If there were statistics and numbers in there he got them across in such a way as I don't remember reading statistics and numbers, just really good story. His webpage has a summary of it if you're interested:
http://www.rosofsky.com/

I know it's late, but...

Even a weather report will use 'creative' techniques to get its points across: it's a wondering wintered land in West Yorkshire... (basic alliteraion).

Ronald Carter puts every written genre (academic, news, transcribed conversation, prose, poetry etc) all along the same continuum (or line) and simply says one piece is more creative than other: creativity has its finger in many pies, not just the one, sort of thing. And in that sense, they are all creative texts to a certain degree.