Portraits are notoriously difficult to get right... Children never stay still for long
It is a good effort and you'll no doubt improve with practice .
Im a bit of a portrait newbee myself but have picked a few tips along the way
Have a look
HERE
I would advice
Use flash when needed ( although natural light is best even if flash will be used for fill in)
Be very aware that the
background can make the difference between an interesting snapshot and a "Portrait"
ie frame with care and/or get yourself a lens like the 50mm 1.8 which is fast ( enable the use of limited light, and at wide aperture blur out background)
Use RAW if you can, it can save exposure , WB errors , and of course there is always PS or Elements for afterwards
If you have a Tele Zoom like the popular 70-300 (sigma DG APO) or similar it is also a great portrait lens nearer its wide end
In the spirit of "practice what you preach"

,
see these from me 3 below
The first was taken RAW with a 50mm lens and the background framed with as little clutter as possible . I was able to get a 20 x30" canvas from it.. a handy retirement gift for her: I used PSE5 to clone out unwanted shadow, a little mess on the wall.
The second was also taken RAW with the 70-300 Sigma : almost no PP. That is my daughter.. she's 6
The third 50mm RAW, minimal /No PP.. A nephew : He was trying to look "serious"
http://farm2.static.flickr.com/1110/...cb7a5386_o.jpg
http://farm1.static.flickr.com/191/4...3cd37399_o.jpg
http://farm2.static.flickr.com/1315/...129a64d9_o.jpg
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