Scale
Scale is simply the size relationship between the objects in your image. I'm sure many of you have seen either pictures or video of leaf-cutter ants carrying the leaves they use for food. Knowing the small size of the leaf itself, and how gigantic it appears in relation to the ant carrying it, the viewer is given a true sense of the miniscule size of the ant.

You can also use scale to make a statement about something. For example, let's imagine you've taken a picture of a farmer. On one hand, you can make the farmer very small and surrounded by a huge field of wheat. In this instance, the message is the size of the farm. On the other hand, you could do a close-up on the farmer and the impression would be entirely different.

Arrangement
How you arrange the elements of your image can make all the difference in how it's interpreted. Useless junk will draw attention away from the focus, cluttering the image unnecessarily. Objects that are not essential to the composition should either be physically removed, or eliminated by changing the camera's perspective.

Compositions that contain strong patterns or lines benefit the most by placing the subject at the central focus of the pattern. Placement of the principal subject should follow certain other general rules as well.

In general, you don't want the subject too close to the edge of the frame, but you don't want it perfectly centered either. Not centering the subject is not a hard and fast rule though; it's one that's meant to be broken now and again as circumstances dictate. Remember, this is an art.

In landscapes, the horizon shouldn't be at the exact center of the frame, distribute the sky or ground according to which element you want to accentuate the most. When taking action shots, show your subject as entering the frame, not leaving it, by having more space in front of the subject and less behind it.

For the most part, when it comes to portraiture you want to show more of the space in front of the subject than the space behind the subject, unless there's some element of the background that's integral to the shot.

But don't sacrifice your subject for a tertiary background element. Figure A shows an example where the photographer was so determined to include a background object he lost a portion of his subject. This is definitely a no-no.

FIGURE A

Don't include background objects at the expense of your subject. Click picture for a larger image.

A better compromise would be to adjust the composition so as to include both elements. And how is this done? You can make your center of focus a point equidistant from each object, or change the camera's viewpoint. In Figure B, you can see a nice compromise between the subject, and the rocking horse. To be fair, Figure B would have had an even better composition if the camera moved down a bit, reducing some of the background above the child's head.

FIGURE B

Center your shot between the desired elements. Click picture for a larger image.

Ideally, you want the subject to be the most conspicuous object in the picture, whether by size, contrast, or positioning. If your subject looks flat or unappealing from straight on, try shooting from an angle.