Hitchcock says that cutting (film editing) should not be thought of in terms of "cutting" but rather in terms more like "assembly" or "Mosaic." Mosaic is assembling something to create a whole that is bigger. In this sense visual storytelling is 1+1=3 (or some other number greater than two). The sum of the pieces you assemble will be bigger - more emotional or more impressive or more memorable, etc. - than the mere total of the individual pieces. Below is a summary of the three approaches touched on by Hitchcock in the clip.
(1) Juxtoposing images in rapid succession
Many people think of cutting, Hitchcock says, as a series of frames following a subject a long a path with a closeup or two thrown in. Hitchcock refers to D. W. Griffith who was a pioneer in the effective use of film editing a hundred years ago. Hitchcock says that editing (montage) goes much deeper than that. He refers to the shower scene in the Psycho as an example of what he calls a more cinematic approach to assembling visual content.
(2) Orchestration of images to create compelling contrasts
This approach looks at the pieces of assembly as soft notes and loud notes and the multiplicity of the variations. The key here is contrast. The example Hitchcock uses is from the second murder in Psycho. Here various compelling medium shots are contrasted suddenly and unexpectedly with an extreme closeup — the equivalent to going from a series of soft notes to a sudden loud note. The effect in this case was shock, but the technique of dramatic variation of size of an image could be used to achieve other desired emotions in the audience as well. (See this interview clip for more discussion on this scene.)
3) Choice of visual can dramatically change meaning
Hitchcock calls this "pure cinema." The power of an image to evoke meaning. No words are necessary. Meaning can be changed dramatically depending on what image you choose to use (or not use).
Keynote slide, image from iStockphoto.
Note: Many storytellers of all sorts including presentation professionals have referred to the lessons from Hitchcock over the years. Nancy Duarte, for example, touches on a few lessons in her book Resonate. And Michael Moesslang has written a whole book (in German) called So würde Hitchcock präsentieren.