When photographers talk about the rule of thirds, they say sometimes they will break the rule and still the photo will have great composition. When should I stick with the rule of thirds and when should I break it? And when I break it, what should I use instead to drive eyes to specific points in the photo?
The rule of thirds to me is a rule of thumb, a reminder not to mindless frame my subject dead centre of the frame, or else I will probably end up with static or boring images overall.
As a beginner, it's a good rule to keep in mind. Not to blindly follow, but to help encourage you to try different framing, perspectives and so forth. As an experienced photographer, you'd probably not even think about it but you'd naturally tend to frame subjects off centre to make them more interesting.
Specific situations where rule of thirds might be "broken"? I would say primarily this is where symmetry is the focus of the image:
if you have a nice, symmetric water reflection, you might place the horizon in the centre of the image to give equal space to the subject and its reflection
in landscapes, if you have an interesting sky you tend to place the horizon towards the bottom of the image, or if sky is bland, place the horizon towards the top. But if you have an interesting foreground and a dramatic sky, you might give them equal weight
close ups of people and pets, like the dog in mattdm's link, especially where there is nothing in the background to balance off the subject. If the subject is interesting and engaging enough, centre placement might be all that's needed.
symmetrical subjects, for example the Taj Mahal. Beautiful symmetry might be accentuated by centering it in the image.
portraits, especially formal ones tend to be centred. Environmental or street photography would be different, where the background can be very important to the image so it needs more weight than a plain paper/muslin background.
For specific effects
The bottom line is that you are the boss and if you think it looks good then don't worry what the rest of us think!
Given that, here are some suggestions...
Placing a subject in the centre can:
- give an impression of strength and stability. (especially if you shoot looking up at something / someone).
- emphasise symmetry in the subject or environment
- be appropriate where your aim is only to produce a faithful representation of an object. e.g. when documenting an object, or for some technical architectural photography
... Or you might go the other way and place a subject right at the edge of the frame. An example is someone peeking into the frame. This makes the viewer think about what is outside the frame, and creates a not-entirely-comfortable feeling that the image is out of balance. Usually photographers want to avoid this, but if it is what you are looking for in your work then go for it.
How to drive the eye?
The human eye:
- naturally follows diagonal lines
- naturally follows the gaze of the subject(s)
- is drawn to faces (especially the eyes)
- is drawn to bright things
... that's a bit of a random selection, but I hope it helps.
The best way to know how, and when, to break the rule is to consume photography - eat up other people's works and develop your taste, find what you like and who you like. Soon, you'll develop your eye to the point where you know how to compose a scene to best do that subject the way you wanted it.
The other suggestions are good, for giving you a general perspective of what effect certain compositions might have, but they are just the outward effects of innately being able to compose a scene from having consumed enough photography (and other art, too) of others.