You're definitely improving, and this isn't a bad set (cute subjects always make life easier), but, just so your ego doesn't get too big,
I'll point out a couple of issues I see...
1. No real catchlights in the eyes, which means they lack the sparkle that is so critical to really good portraiture of this type. As mentioned, the face is a tad dark. A silver reflector here would have taken this shot from good to great. Watch the details; there's a couple of patches of red in the background image left which clash with the subject; clone them out. The purple of the chair is rather harsh as well; ideally you should have had her sit back and obscure the chair, but failing that, perhaps tone down the colour in post a bit? I would prefer to see her hands as well, and have her looking toward the camera.
2. I see some WB issues; the green channel is a tad high here. and the highlights in her dress and his shirt are a bit hot. That combined with a slightly too bright sky means the eye is being pulled from bright spot to bright spot, but spending very little time on the faces of the children. A speedlight in a medium SB would have really helped here; you could have balanced out the foreground and background, knocked down the sky and the clothing. Also, watch the background; the row of posts make a great leading line, but they lead the eye PAST the subjects; ideally, when using leading lines, locate/compose so that the subjects are at the vanishing point.
3. Pretty much the same technical comments as per #2, with the addition that the child is perfectly centered; not usually a desirable or visually pleasing composition (but easily fixed with a simple crop in post).
Overall, they're not bad. Most of the points I (and the others) have raised are relatively minor, and things to keep in mind and practice, which, once learned and applied, will separate you from the herd, photographically speaking.
Just my $00.02 worth - your mileage may vary.
~John
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