Firstly, wow this is an amazing and cute piece! As a whole is is very eye catching when viewed as a thumbnail and mad me want to click to view it in more detail; so that is a major plus when it easily stands out among others.
In regards to the overall image I love everything about it!
The coloring, shading, and lighting all blends in perfectly where they need to show the depths and softness of all included in the image.
The composition is well done, even with everything near one another nothing in this image feels clustered and every aspect flows smoothly, giving the baby, dog, bucket of stars, and background equal attention.
The background is neat and simple which is only enhanced by the soft coloring of the clouds.
I very much like the semi-realism of the baby and the slightly cartoonish style of the plush dog. I also enjoy the emotions in the baby's eyes, you can really see the childish glee in them.
Only complaint I have is the white boarder, I think it would bring the entire piece together more if the clouds and background filled the rest of that space.
Other than that, wonderful job! Keep up the good work!