But now that you have decided not to use the automatic settings or the default lens, what choices need to be made? I will discuss one of them; depth of field.
Depth of field relates to the compression of the front-to-back distance in your image. The larger the perceived distance, the larger the depth of field. A long lens tends to give a larger depth of field. A short lens or wide lens does the opposite.
I found a useful demonstration of this on Understanding Depth of Field ...
The above image is that of table, whereas halfway into the distance the image is sharpest. Compare the sharpness of the glass in the front with that in the middle for example.
Using depth of field effectively can change the perception of the viewer, thus assisting in telling a story. Examples are pictures that at first sight look like miniatures, but are a result of what is called tilt-photography.
Example of a tilt-photograph using depth of field by The Bitter*Girls
An in-depth (no joke ;o) explanation of tilt photography is available at Photo.net.