Get to know your camera better in this digital cameras tutorial, which offers basic and more advanced photography tips.
In any photo you take, you'll want your subject to be in focus. However, sometimes you may want the background to be out of focus to give a soft, artistic appearance to the photo. This is known as shallow depth of field. With a shallow depth of field, you can still focus on your subject, but objects that are closer or farther away will be out of focus. If you are using a DSLR or bridge camera, you can get this effect by choosing a wide aperture (such as f/1.4).
In the photo below, the depth of field is shallow, completely blurring the background.
Smaller apertures (such as f/16) will give a deeper depth of field, which means more of the photo will be in focus. For example, if you're taking a landscape photo you'll usually want a deeper depth of field so distant objects and foreground objects will all be in focus.
In the photo below, the depth of field is very deep, allowing the flowers and the mountains to be in focus (as well as everything in between).
With a point-and-shoot camera, you won't have as much control over the aperture, so it may be difficult to get a shallow depth of field. If you want to get a shallower depth of field, you can zoom in or move closer to your subject. However, if you really want to experiment with different depths of field and have more creative control over your photos, you will usually need to use a DSLR or bridge camera.