I have found the "Flash Exposure Lock" very handy (it's the asterisk button, when the flash is down/off its the "Exposure Lock" button, also handy). For example:


1) The A-TTL flash exposure meters towards the center of the viewfinder, so if you focus on the subject and recompose with the subject off to the side, whatever is now centered will be properly exposed by the flash. So if you want to take a picture of a friend standing next to, but technically in front of a sculpture, if you recompose with your friend off to the side, he will be overexposed by the flash. The reason is that the flash is now metering off the sculpture that is further away, and requires more light. To avoid this: Center on your friend, press the "Flash Exposure Lock", whichs fires the flash and takes a reading off the center of the frame. Now recompose (do not change the focal length) and shoot, as long as the asterisk is showing in the viewfinder. You may be tempted to merely use a focus point that is off to the side. It won't matter, the flash meters from the center only.


Some other ideas:


-Using a zoom lens, stand back and zoom in so the flash isn't such a harsh blast.


-The use of the flash in "Aperture Priority" and "Shutter Priority" modes is for fill flash only. The camera is exposing for the background. But in indoor light, or low-light situations, be prepared forshallow depth-of-field, and a soft image at low ISO's. The picture of your boy in front of the Christmas tree would benefit from this method. You will have the choice of 1/60 or 1/200 shutter speed, depending on how dark or light you want the background, and higher ISO's can help too.


I hope this helps!