Because the camera is not as selective as the human eye, photographers need to use a range of composition techniques to add emphasis to their images and direct the attention of the viewer .
Therefore, one of the first decisions you need to make is with regard to your choice of focal point - what is the main point of interest that you want to draw the viewer's eye when they look at the photograph.
It seems the single biggest problem with the images of new photographers is that they fail to consider what their subject actually is. If you are not aware what your main subject is in an image it is hard to emphasize it in the final composition. This leads to confused,unstructured and cluttered compositions in which there is too much background detail and nothing specific the viewer to look at.
Decide what your subject is and then rearrange the image to emphasize it.
Always remember that the camera tends to record too much detail and controlling for depth of field you can reduce distracting background or eliminate it altogether if it does not relate to the subject. With fewer visual elements to arrange, you have more control over the composition .
Albert Allard, photographer to National Geographic
"What's really important is to simplify. The work of most photographers would be improved immensely if they could do one thing: get rid of the extraneous. If you strive for simplicity, you are more likely to reach the viewer."
When your subject is too expansive to be considered a focal point in itself such as in the case of landscape, try to contrive a focal point that adds some relief for your viewer.
Add a secondary choice of focal point such as a mountain cabin, a distant lonely tree or a group of hikers near the horizon to allow the viewer's eyes to rest on something familiar, even though the real subject fills up most of the frame. You can see how this is used in the below photographs.