OK, so here are my thoughts... you might not like them.
These seem to be all underexposed, with the exception of the very last one.
The first one is cute, but you chopped off his hands and that just killed the entire picture for me.
The 2nd one with the boy looking straight into the camera on his tummy, looks like there is a lot of distortion, probably from focal length? And the sky is completely overexposed and the subject underexposed, its just not good.
The third is a cute capture, although, again, very underexposed. You needed to be taking pictures when your subject was facing toward the light, not away from it. You can add a reflector of course, but if you do not want to carry around or fuss with when, then you need to get your subjects lit properly with the light you have, while avoiding direct sunlight. I tried to fix the third one for you in post, its better, but could be so much better if there were a little more thought going into the taking of the picture.

The last one is the best. You've got a decent candid shot there. The far side of his face is overexposed, I don't like that the floor board is at a diagonal slant, and the picture needs to be warmed up a bit, but over all, not bad.