(01) Use a Tripod, if at all possible.
Tripods are by far the best method of ensuring image sharpness right in the camera. Ensure the platform created by your tripod stabilizes the camera such that camera shake due to human interference is not an issue, regardless of the level of light available to you, and thus the length of your exposure.
2) Use a Proper Handholding Posture when a tripod is not practical.
When tripods are not practical or if you don’t have access to one, you should assume the proper handholding posture to minimize camera shake:
Hold the camera with both hands such that your right hand has a finger on the shutter release button, and your left hand cradles the camera body (not the lens – it’s ok to rest your fingers against the lens, but be sure you don’t interfere with auto focus).
Press your elbows tightly against your torso and raise the camera to eye level (for SLR) or so that you can see the LCD (digital P&S), but never hold the camera with extended arms as this increases shake.
Stabilize your body against a solid object if you can – a wall or lamp post will do. Use the focus lock feature by depressing the shutter release button half way; once the focus is locked, take a deep breath, and depress the button fully & gently to take your shot while exhaling.
3) Use Image Stabilization (IS) or Vibration Reduction (VR) Lenses.
Some lenses for SLR cameras include built-in methods of reducing camera shake. If you have such a lens, make sure you enable IS or VR when shooting hand-held. This technology reduces the effects of camera motion on image sharpness by countering the slight lens movements that result in a blurry image. In general, these lenses allow you to hand-hold a camera at a full stop increase over non-IS or non-VR lenses.
4) Adopt a Faster Shutter Speed.
5) Use appropriate Aperture.
The rule here is that your lens does its best focusing when set to two stops smaller than its widest aperture. For example, if your lens’ widest aperture is f/2.8, then it will produce the sharpest images (not at f/4) at f/5.6. Even high quality lenses with aspheric and low-dispersion glass elements may not produce their sharpest images at their widest apertures.