One of the keys to getting sharp photos with digital cameras is to completely stabilize the camera when taking a shot. If you can, use a tripod, monopod, or a handy fixed object such as a ledge or a rock to stabilize the camera. When pushing the button to take the picture, push it gently.

If you must hold the camera, use two hands, tuck your arms elbows into your body, and hold your breath when you take the picture. Make sure you are standing in a stable position. You do not want to take a picture with your arms extended when you are holding the camera... it'll be moving all over the place and your photos will suffer as a result.