Using tablet and not follow step by step practice = EPIC FAIL. OTZ

At first, I just drew this as doodle. Then I did the outline and colored it and ... bah bah bah.... and, at last, it isn't doodle anymore.
I'm not satisfy with it at all, especially BG. But I don't know how can I do it better. OTZ
And I'm lazy with this, I re-colored it about 2 times and it is enough now.

At least, hope you like it. And please comment with no mercy, I want the improvement.

Silver © SEGA/TEAM SONIC