animal shots ain't my thang (especially since I'm not particularly fond of dogs--but I'm sure that yours is the exception and I'd love it

)
Seriously now, if you are noob, than this is a good first attempt. You captured a great expression on the pup's face, and from what I've gathered, if that part was intentional on your part, then you don't have much else to learn...just some technical stuff.
LaFoto's idea is right on the money. Also, You cut the poor pooch's feet and tail off. Think about all parts of the dog. If you want a full body shot make sure you get those bits in as well. Crop the dog's body like you would a person...that is, if you want a headshot, then capture only that. Also with headshots I've been told you should have space into which the dog is looking for balance.
Now, having said all of that, I've only really tried animal shots once, and if you want to see what I came up with, which I don't think is very good--cute as hell, but not very well executed--click
here. As you can see, I cut the poor girl's pointy little ears off.
So, I guess you should pretty much ignore my advice and wait for others smarter than Jo Cose to offer advice.
Thanks for posting, and keep em coming...that's the best way to get better.