The following information comes from various Web pages and helps to explain SOME of the basic elements of good composition & photography. These elements are true in all forms of photography whether it’s architecture, landscape, or photographing people & models. These rules are as old as paint and canvas and really stand at the core of how our eyes processes imagery. It should also be noted that you should also know when to break these rules.
RULE OF THIRDS The rule of thirds has been used through the centuries and is probably the most recognized rule. The rule of thirds directs that the frame can be divided into three vertical sections and three horizontal sections. Wherever the separating lines connect is an ideal spot for a subject or point of interest. By positioning your main subject at any of the four intersection points, you are giving your subject more emphasis than if it is right in the middle of the photo. The intersection points can also work if there is more than one main subject in a photo. Most famous photographs and paintings have the rule of thirds applied to them in some way or another
SIMPLICITY The simplicity rule directs that you should keep the items in your photo relatively simple. If your main subject is close to the lens, then your background should be very simple in order to avoid distractions. Another good idea is to avoid objects or lines that lead the eye away from your main subject.
CONTRAST The contrast rule directs that light subjects should be placed against dark backgrounds and vice versa.
FRAMING The framing rule directs that using natural surroundings mindfully can add more meaning and focus to your subject. The surroundings could be anything such as bushes, windows, trees or even a doorway. When using this rule be sure to focus on the main subject and not on the surroundings that are framing it. It is also a good idea to use a narrow aperture (high f/stop) when using this rule in order to create a high depth-of-field.
TEXTURE The texture rule can add a great amount of interest to most photos. When people see texture in a photo it can spark their imagination and make the photo more real to life. Texture would be a good idea when taking photos of rocks, walls, surfaces, hands or even leaves. In order to create texture try to compose your photo so the light is coming from the side and therefore casting shadows in key places.
DIAGONALS The diagonal rule directs that diagonal elements or lines can make a photo more dynamic. Diagonal elements could be fence posts, roads or even tree branches.
LEADING LINES The leading lines rule can be used to direct the eye deeper into a photo and commonly to the main subject. Leading lines can lure the eye to a subject by leading to it from any side or depth of the photo. Leading lines could be roads, rivers, tree branches or even bridges.
COLOR The color rule is what adds interest and emotion to your pictures. Different color configurations can inspire and amaze viewers. Colors can also be used to accent certain parts of a photo.
From Bob J About color: In some instances, the absence of color, through the use of black & white images can also create an emotion. Color creates an overall tone or theme, and effective use of color or black & white can set the tone or emotion of the image.