The background isn't bad, it's pleasant to look at, though there's not much there. It's plain.
Not to be harsh but I'd suggest working on anatomy before posting in intermediate.
Take this as a reference of the body of a sitting greyhound:
http://image.shutterstock.com/display_p ... 424195.jpgImage not mine, I take no credit.
Greyhounds have unusual body structure, but try to keep it realistic. Greyhounds and other long, tall, skinny breeds are hard to draw imo, though you may differ.
Good luck. Again, don't take this as an insult. It's merely constructive criticism.