Now here's another example of the ol' rule of thirds. In this particular case my wife's head is pretty much at the intersection of the top left hand intersection point.
But this post is about something else. Where the subjects of your photo should be looking. As a general rule, if the person (or animal) in your picture isn't looking directly at the camera then they should be looking into the frame.
In other words they should be looking towards the centre of the picture, not outside the frame. There's a couple of reasons for this. The first one is that when the person is looking into the frame the natural inclination of the viewer of the picture is to look at what the person in the pic is looking at.
Try it with the picture above. Your eye first of all goes to my wife's face and then follows her gaze out, and thus you look at the rest of the picture. It's more subliminal than product placement in movies!
The second reason is that when you have a person looking out of the frame, in other words they're placed in the edge of the picture and their face is looking towards the edge of the picture with lots of space behind them, they look very isolated.
No matter what the expression on their face they look separate from everything else happening in the picture. Disconnected. Isolated. Lonely. You often see that technique used in news photos. Think of a picture you've seen where somebody has lost a house or something like that. They will always be in the edge of the picture looking out of the frame with their house behind them. It makes them look sadder than if they had been photographed looking into the frame at their house.
In the case of animals it's pretty hard to make them look sad but it does make it look like you missed the moment. That you took too long to press the shutter and the animal has nearly moved out of the frame on you.
Have an experiment with this one. Take a couple of portraits of somebody you know with the same expression on their face. Try a smile to make the experiment really effective. Take the first shot with them in the left hand side of the frame facing right (ie into the picture). Now leave them where they are and move the framing of the camera so they are still facing in the same direction but now the wide open space is behind them and they are facing out of the frame.
I guarantee you the result will be completely different. When you've had a go at it try posting them to the Flickr Group and I will be happy to give you some advice.