Exposure simply refers to the amount of light recorded on the film or sensor. You want the right amount of exposure to capture the image you see (or are trying to create). If you shoot a daylight scene with too much light hitting an overly high ISO sensor for too long, you'll end up with an overly bright, glaring, unrealistic image. On the other hand, a small aperture at low ISO and short shutter speed could make a daylight scene look dark and murky. Balancing shutter speed, ISO and aperture to get the correct exposure is the key to great photography. Master this juggling act and you'll be well on your way to consistently taking great photos. (And if you have no idea what any of this means, we'll explain each of these terms later in this article.)
Luckily, there's an easy way to cheat on your exposure juggling routine. It's called bracketing. To bracket a photo manually, set your shutter speed, aperture and ISO to where you think the proper exposure is, then take the photo. Then, adjust your aperture or shutter speed to reduce the exposure slightly and take that photo. Then adjust the exposure so it's slightly more than the first photo and take that one. This series of three photos "brackets" what is, hopefully, the proper exposure. Try to hit the sweet spot between the three to capture the perfect image.
Most digital cameras make this even easier with an automatic bracketing mode. When this is turned on via the camera's settings, the camera will automatically take three photos, with properly adjusted exposure settings, every time you press the button.