A more accepted approach is to use capitalized headings to break up a scene, such as Robert Towne uses in the screenplay for "Chinatown," in this scene in which detective Jake Gittes follows Hollis Mulwray.

DOWN ON THE BEACH

Gittes looks to his right -- where the bay is a long,
clear crescent.  He looks to his left -- there's a 
promontory of sorts.  It's apparent Mulwray has gone
that way.  Gittes hesitates, then moves in that 
direction -- but climbs along the promontory in order to
be above Mulwray.

The DOWN ON THE BEACH heading is like a sub-slugline that immediately designates a master shot, whereas the other sentences of the paragraph suggest other possible sub-shots; "he looks to his right," for example, hints to the director that he could perhaps use either a straight cut to show the "clear crescent" of the bay, or perhaps even cut to a shot of Gittes' POV, and pan first right to see the bay, then left to see the promontory.

Modern screenwriting style typically breaks down thick paragraphs like the one above into single sentence lines. These single sentences alone also suggest individual shots.

A particularly violent scene from "The Usual Suspects" perfectly illustrates how to write an action sequence that suggest separate shots. This scene is done without capitalized sub-slugline headings (except for sound effects), although screenwriter Christopher McQuarrie does capitalize the beginnings on sentences for emphasis. His capitalization is purely a stylistic choice, and is in no way required.

INT. VAN
          
Hockney laughs and jumps in, suddenly oblivious to the
sound of gunfire.  He opens one of the crates and looks 
inside.

IT IS FILLED WITH MONEY.  Cash and negotiable bonds of 
all kinds.

He smiles.

BOOM

BLOOD sprays all over the money.
  
Hockney looks at it, puzzled.

He turns and sees one of the men in suits holding a 
shotgun.

Hockney looks down at his own open belly, blood and 
innards flowing freely.

BOOM

Another shot takes off the top of his head.

McQuarrie's description is effective, simple, and easy to read -- everything a good script should be. It is always a good idea to break up big blocks of text in this manner.

It is important to remember that the basic function of script format is the same as for all writing -- to clearly convey information. Occam's Razor is a principle that states that the simplest solution is usually correct. If you keep this in mind when formatting scripts, you'll succeed in conveying the necessary information in a way that makes sense and will not call attention to itself. Soon, you'll be able to invent formatting that derives from the basic rules but still looks correct, which will allow you greater creative freedom as a writer.

"Chinatown"
Script by Robert Towne.

"Star Trek II: The Wrath of Khan"
Script by Jack B Sowards, story by Harve Bennett and Jack Sowards.

"The Usual Suspects"
Script by Christopher McQuarrie.

Screenplay Format According to the Academy
The Nicholl Fellowship page showing proper screenplay formatting.

How to Format a Screenplay
From ScreenStyle.com, a great overview of the basics of script formatting.

"Beavis & Butthead Do America"
Script by Mike Judge and Joe Stillman.

"Star Trek IV: The Voyage Home"
Script Harve Bennett, & Nicholas Meyer, story by Steve Meerson, Peter Krikes, Leonard Nimoy and Harve Bennett.

"Pleasantville"
Script by Gary Ross. Undated later draft.