C&C per req:
1. A nice, casual child's portrait. Exposure and focus are bang on and composition isn't bad. Generally when you have the subject looking at something away from the camera like this, the image is stronger if the viewer can see what it is as well.
2. Hmmm... The monochrome is a rather mid-tone rich and over-exposed. Not the blown highlights and lack of detail in her shirt-sleeves and on the crown of the stuffed toy. The image appears softly focused. Watch your crop/composition and try and avoid things like the little bit of missing elbow. If you must crop limbs, do it boldly!
3. Not really fond of this one. The large, unfocused pillar image left is very distracting, and the slight angle makes me want to tilt my monitor. Crop the LH side and level the image.
4. Slightly over-exposed, but definitely salvable. It appears that focus was on the stuffed toy rather than the face. Always ensure that your focus points are where you want them. In portraiture, I almost always recommend using a single focusing point and make sure that is on an eye. Again, not the cropped elbow and right hand.
5. Good, slightly dark in the eyes; a reflector low and in line with the camera would have helped. Watch for things like the thread on her right cuff. Exposure is spot on.
6. As per #5.
Overall, I would say this is a very good first effort. There are a few issues that you need to work on, most notably ensuring sufficient fill light in the eyes, but a strong showing nonetheless.
Just my $00.02 worth - your mileage may vary.
~John