Just glancing back through some of our past assignments, here are some ideas for "breaking the rules":
Isolation: Instead of isolating your subject, "hide" it in the composition or background (a tiger peaking through the tall grass, etc)
Color: Compose an image where the color is inconsistent with the subject (a tough looking cowboy wearing a pink hat)
Balance: Produce an image that is "out of balance" where elements on one side of the image have much more "weight" than the remainder of the image. This "unbalanced" feel can be used to enhance the user's feeling of "unease" about a particular subject.
In the balance assignment we also talked about the "rule of thirds" so break the rule and try placing your primary subject someplace other than the intersection of thirds.
Soft Light: Instead use "hard light" to produce a "grittier" image or an image without depth
Linear Perspective: Produce an image where the depth cues are reversed, with the smaller objects in the foreground, and the larger objects in the distance. Come on, see if you can do it!
Atmospheric Perspective: Same thing. Produce an image where the foreground is in the atmospheric haze and the distant objects are sharply defined
Texture: Use completely flat lighting to remove shadows and "texture" from an object that the viewer would expect to have texture
Warm Light: Instead, use "cold" light to produce an unwelcome or "cold" feeling for the image.
Distraction Free: Produce an image with "distractions" (but have an artistic purpose for including them)
Harmonious Colors: Produce an image with "discordant" colors that will jar the viewers sensibilities.
Patterns: "Break" a pattern
Eyes: Create an image where your subjects eyes are obscured (in shadow perhaps) so that the viewer cannot "connect" with the subject
High Contrast: Instead of trying to control the contrast, let the highlights blow, or shadows go dark in order to produce a more stark feeling for the image
Simplicity: Complexity
Depth: Instead, try to produce and image with NO depth cues. Come on, see if you can do it. I dare you!
Wide and close: Small and distant?
Bokeh: Produce an image with horrible, awful looking bokeh. Double vision type bokeh that makes the viewer cross eyed! If you try hard enough I'm sure you can find a lens and aperture combination that produces horrible bokeh. (But have an artistic reason for doing it!)
Sense of Place: Include objects in the scene that break the continuity or look jarringly out of place. Again, have an artistic reason and "message" to convey.
Fill Flash: Instead of trying to make it look natural, strive for an unnatural look, over-flashed or with harsh, unpleasant shadows. And your artistic reason is?
Pastels: Include a saturated fluorescent color in a pastel scene.
Framed: Hmmm. That's a tough one. Can someone produce the opposite of a "framed" image?
Leading Light: Instead of leading to your subject with light, use shadows to hide your subject.
Telling a Story: Hmmm, another hard one. Try composing an image that DOESN'T tell a story. :-)
Clarity: Obscurity
Specular Highlights: Instead of "letting them go" try protecting the specular highlights and letting the rest of the image go dark
Leading lines: Lead away from your subject
Rhythms: Break the rhythm
Contrast: Instead of trying to control and minimize the contrast, enhance the contrast to produce a 2-dimensional image without depth cues, or a "harsh" image with no texture or detail
Separation: Try producing an image with NO separation between the subject and it's environment. Use flat consistent light, extreme depth of field, no shadow differentiation, etc. to blend your subject into the scene.
Detail: Break one of the rules by inducing motion blur, etc.
Composition rules: Split the image in half with the horizon line, place your subject in the center, or otherwise violate one of the "rules" of composition you may have read about.
These are just some ideas. I'm sure you can come up with more, so have fun!
Keith