That or film history, historical context, production, actual firsthand knowledge or research performed. Nowadays this has gone out the window with everyone being able to simply look up anything in a matter of moments and be a self-described expert.
A great and often recurring example of this for me is discussing any of my favorite directors, who have been heroes to me since childhood. Few study the people behind the films; their histories, thoughts, ideals and actual intent-let alone the production scenarios. Most of all I come across people which leave me responding like this: "Oh, so you possess a Hitchcock expertise do you? How did you feel about the effectiveness of Under Capricorn? Saboteur? The Paradine Case? Which ending for Topaz works best to you? Which of the abandoned projects do you lament the most? What did you think of the intricate subtleties in Rope? Do you agree that Foreign Correspondent is superior to Rebecca? How do you think Hitch's collaboration with screenwriters worked best? Which of the renowned films do you find flawed? " And as with everything of this nature, I'm not angry but intensely sad that people simply don't care to know what they are talking about or even bother to see the films.
I grew up devouring every film book I could get my hands on, most of them being moth eaten, rotted, tattered and torn from libraries. Then I had to track down the films on VHS tape and hope they weren't in shoddy transfers. My knowledge is pretty much lifelong self-taught, and I would be the first to admit that I don't know everything.
Toying with the idea of doing video reviews is a nice one, but every youtube iteration of this devolves into either simple talking or the usual rant/rave. Then you have those who wind up inadvertently developing recurring characters out of it, such as RLM, AVGN and the Nostalgia Critic. Yet when you go this route it becomes harder and harder to actually criticize and make eloquent points about the material because you are having to serve something else now.
There seem to be two polar opposites, those who live and die by proper critical work and non-professionals who couldn't care less about form, knowledge or structure. Really one has to be honest in this type of work and develop a singular voice entirely of their own, and then actually say something with it.
This is what I try to do when I write, by injecting enough of myself into the writing in order to reach a new tack or idea that I wouldn't have been able to if just looking at the material coldly and objectively. Officially and absolutely my problem with writing film criticism is that I feel and care about cinema too much. As I've always told professors, I don't give a damn about being perfect or proper, I only care about doing the films justice and creating unspoken dialogues with people.
This leads me to the problem of length. There is no paper long enough for me to get everything I think or feel about a film down upon. Yet professionals hardly have any time or space to get their points across. Ebert's regular reviews are about 1,000 words long, and in a newspaper column you're lucky to get all of that printed. Video reviews are even more restricting. This is the freedom of internet blogging, but that comes at a price. Length or intensity is not always the answer, and it is often the more simple prose that conveys the necessary feeling.
And I like to keep these relatively honest, with asides and bit of occasional humor, because in the end the entire point is to share and promote the rare gems of art or escapism while provoking thought.