You have a nice family! Here are some quick comments...
I looked at your exif [Nikon D70, flashed fired (assume onboard flash, 1/60th sec (flash sync speed btw), and f4.2 with a (max f of 4)]
Assuming you don't have an external flash (highly recommend a good one and use bounce flash indoors, diffuser semi-direct outdoors).
1. Try setting your camera to full manual mode and start with a shutter of about 1/20 sec, stop at it's widest (4 in this case for your lens), flash in I-TTL with FEC (flash exposure compensation) of -1, ISO 200.
2. try multiple shots with settings in #1 making only slight adjustments to shutter speed stay below 1/20 sec, make most adjustments to FEC and maybe try ISO 400 (depending on ambient light).
Great starter shots...I presume you got an early x-mas present?
Roy