Depth of field can be used to enhance or draw focus to certain aspects of your photo.  Bokeh, which is Japanese for blur, is a technique where the foreground is in focus, and the background is not.  You can achieve this effect by setting your camera to a wide aperture.  An out of focus foreground can be useful when photographing something behind a fence, or something similar.  Moving close to the fence and using a aperture just wide enough to blur the fence, will focus on the background.  A shallow depth of field is used for macro photography.  

Bokeh

Out of focus foreground

Close up

Sign Reflections in Black and White

For this assignment I needed to take 8-10 black and white photos revolving around the theme of reflections.  All of the photographs I took are of neon signs being reflected off of glass or buildings.  I did some research prior to taking my photographs and learned that ideally I would have a 50/50 ratio of blacks and whites, making sure to keep the blackest of blacks and the whitest of whites without losing the greys in between.