Have a look at the two images of the Christmas tree.
Don't laugh at my Christmas tree! Both images were taken with the same camera, a Lumix, not a professional DSLR.
The first is taken with the camera on automatic with flash enabled. The flash will correctly expose your image but in doing so you will loose the warmth and ambient lighting of your Christmas scene. The second image has the flash disabled.
You should be able to do this easily with any compact camera. The camera will then expose the shot by lowering its shutter speed to 1/60th second and by opening up the camera aperture as wide as its lens will allow. The low shutter speed will cause any motion to blur in the picture, this is called motion blur. If you want children or other people in the shot they will have to stay very still! You will also have to position your camera on a fixed surface and put your camera on timer.
So:
Disable the flash
Position your camera on a fixed surface
Compose and focus your shot
Set the timer
Get into position and stay very still.
Check the results.
If you have a DSLR you can achieve a much more accurate and crisp shot: Set your camera to shutter priority or TV.
Set your Shutter speed to 1/100th, make sure your flash is disabled.
Take a shot.
Have a play with your manual settings to achieve the best ambient light
shot, increasing your ISO will give you a grainier image but will allow you totake images in much lower light.
Keep your shutter speed at around 1/100th to 1/125 to avoid motion blur and your aperture as wide as possible f/4, f/2.8 if you can.
