This I am doing at school, plus I already gave you some sites so I'll just get to the point.
This is much better than your others. The muzzle (With is wear most, if not everyone have trouble on) It better. I reccomend doing a sketch first with it being a rectangle. The head being circle. And you gradually connect the two on the bottom (chin like thing) And you've done that well.
With the heat to nose part, you put a tip. Try to smooth that out next time.
The ears are curved too sharply whre the head seensto disappear behind it.
The neck you've done great on. You gradually moved to the shoulders.
Now, if you look up some other art with dogs, you can see their shoulder blades slightly. Those would be a bit higher. But don't put too much stress there, because they don't need to be that visable.
From the body to the leg, I think you can do that a little smoother, gradually. It's too rectangular. But youare getting that much better.
The little pary I can see of the belly is done just right! ^^
Good job on the picture, I think you've done really good ^^ You're getting there!!