I thought I'd begin this topic by defining some basic terms with short explanations.
Shutter Speed(SS):
A fast SS can freeze the motion of a fast-moving subject and a slow SS can blur the subject to give the impression of motion. A longer SS (shutter is open longer) lets more light in to the image sensor (brighter exposure) and the inverse.
ISO Speed:
The ISO speed is a numeric indication of the sensitivity to light. A higher ISO speed indicate a higher sensitivity to light. Therefore, a high ISO speed is suited for moving subjects or shooting in low-light conditions. However, a high ISO photo will contain more noise which makes it look coarse or grainy. On the other hand, a low ISO photo will look finer, but is not suited for freezing motion or shooting in low light conditions.
Aperture value (AV) & Depth of Field (DOF):
The larger or brighter the aperture (lower f/number) the more blurred the background will become. This effect is ideal for portraits. The smaller or darker the aperture (higher f/number), the clearer the focus will be for both rear and far objects (wider DOF. A wider DOF is often used for landscapes/outdoors shooting. To repeat, a larger aperture lets in more light to the image sensor(brighter exposure), and the inverse. Is this pretty clear? If you have any: ideas, comments, or questions, please leave them as comments.