The Rule of Thirds.
One of the most popular 'rules' in photography is the Rule Of Thirds. It is also popular amongst artists. It works like this:
Imaginary lines are drawn dividing the image into thirds both horizontally and vertically. You place important elements of your composition where these lines intersect. I've even made a little diagram for you (fig 1).
As well as using the intersections you can arrange areas into bands occupying a third or place things along the imaginary lines. As you can see it is fairly simple to implement. Good places to put things; third of the way up, third of the way in from the left , you get the idea. Duff places to put things; right in the middle, right at the top, right at the bottom, away in the corner.
Using the Rule of Thirds helps produce nicely balanced easy on the eye pictures. Also, as you have to position things relative to the edges of the frame it helps get rid of ' tiny subject surrounded by vast empty space' syndrome.
One last thing about the Rule of Thirds for the time being. Once you have got the hang of the Rule of Thirds you will very quickly want to break it ! This is fine. As I said earlier these 'rules' are best used as guidelines and if you can create a better image by bending or ignoring rules then fire away.
The Rule of Thirds is fairly structured but there are a great many methods you