I don't know how to describe this but I've thought. Story elements aside. What's a visual trademark or stamp of a director that's noticeable that it's a film from that specific director?

Ex: If Toshiro Mifune and Takeshi Shimura are in a film together..it's a good chance it's a Kurosawa film. (out of curiosity did they make any films together without AK at the helm?)

Or...say...Tony Scott's modern visual style of an in camera effect. You know what I mean.

Christopher Nolan's use of a certain shade of orange and blue specifically from BB to Inception.

Do you guys get what I mean?

John Woo: slow motion, doves, Mexican stand-off, firing two handguns at the same time

Quentin Tarantino: the trunk shot, present in all of his movies.

Thumbnail:

Kubrick - the character "stare"

Robert Rodriguez: Danny Trejo w/ blades

Spike Lee: Camera remains fixed on person standing still while background moves away, giving image that character is "floating" down the street, etc.

I'm not sure how to describe it, but David Fincher's films have a certain look. Part of it is the colors being somewhat desaturated.

Leone: Close-ups of characters' eyes during showdowns, sweeping track shots

Don't forget his foot fetish...

I'll add in Brian De Palma's long tracking shots, often used as a POV shot

You're talking about the color pallate he's used since Panic Room onward. You're right about that.

To DePalma, I'd add his use of split-screen shots to cover multiple angles of action during key scenes.

and multiple focus shots like the foreground and background are both in focus.

Robert Altman: Overlapping dialogue

I believe he's also always had an important scene that took place in a bathroom.

Damn, that's a much better example!

Ozu - chacters speaking to each other are shown facing the camera instead of in over-the-shoulder shots.

Hitchcock: self-cameo

Russ Meyer: busty women

Another Early-DePalma stamp: Killer with sunglasses.

Fellini-Dance sequence
Peckinpah-Slo Mo death
Argento-Hands doing the killing (They're usually his)
Kitano-Are we in a flashback or not?
Demme-Big closeups of the character talking right at you (Courtesy of his trusted DP, Tak Fujimoto)

Sam Raimi and his twisty Ram-Cam thing.

What would Scorsese's be? Quick, extremely deliberate cuts?

Michael Mann does that thing where he angles the camera at the sides of peoples faces with a soft focus. It usually has a heavy tint, depending on the mood of the scene.

Its a beautiful little trademark. It's in all his films from Manhunter to Public Enemies.

Tarantino didn't direct From Dusk 'Til Dawn *sniff* [/film nerd]

Cameron - use of blue tint
Spielberg - shooting star in a lot of his earlier work

John Carpenter (circa '76-'88) - a group or individual is confined to a specific location with limited resources and claustrophobia begins to set in

Tim Burton always seems to have something black and white striped his movies. Beetlejuice snake, etc.

Wong Kar-wai and slow-motion cigarette smoke.

True, but he did pen the screenplay, and he probably purposefully wrote the scene in that fashion.