There are several factors that can contribute to getting better focus and improved results.
1. Auto Focus / Auto Exposure lock. Press the shutter button down HALF WAY. The camera will attempt to adjust exposure to the current lighting environment for maximum benefit. Then the camera will automatically correct the focus based on objects in the center of the display. If the camera can automatically set the focus and exposure, the LED by the viewfinder will turn GREEN. If the camera can not adjust the settings automatically, the LED will turn RED. This process usually takes about two to three seconds.
2. Be sure not to cover the sensor on the front of the camera with your finger. This will disable the automatic focus and exposure controls.
3. Rely on the Rear LCD Display. When in doubt, trust the LCD. The LCD will display the subject more accurately than the viewfinder. This will help with "framing" the subject, or determining if you have enough light for proper exposure.
4. Motion can cause a "blur" effect. Either motion of the subject, or motion by the photographer. This phenomenon is just like traditional photography. Moving objects may appear to blur, and this will be even more evident in lower lighting situations as the shutter speed slows down to allow for more light. The shutter will react faster in bright light, and motion will not be as apparent.