ok here goes:
the first one is oddly framed. you included all this useless stuff way above who I am guessing is your son's head. why is it there? instead of doing that, stoop down, get at the same level as him, shoot level to the ground, and fill the frame up with him, not the blurry woods behind him.
The second one is ok except you've done the same thing (subjects at extreme bottom of frame) and the little dude in front looks like he snuck into the photo... or he's sleep walking... can't be sure which. your aperture is too large too, because he is starting to go out of focus. remember to stop down when shooting groups. Otherwise you'll have problems like this.
In the last one, you've missed focus also. the focus is in front of the subject. Make sure to always focus on a person's eyes. if the eyes are in focus, the entire rest of the photo will look in focus. If not, it just looks out of focus. This shot is also one that would have benefitted from you getting on one knee.
Always shoot "across" at your subjects, never "down" on them.
Hope this helps!