It's cute and funny, they're are a few mistakes that stop
it from being great though.

I think it would have been better had you stayed straight with
the color of your outlines. The way you changed it makes it hard to
see it, the switch is so sudden and kills the look on it.

Also it's a bit jagged around some areas, the hair, hand and
a bit around the arm stick out mostly to me.

As for the background it's nice, I think the water
could use several more shades on it though. The moon could
maybe use less color and give it a nice fade then glow, the sky is a bit
empty and then looks unbalanced and weird with those random star bits in some areas.

The clouds are alright, not much to say on them.

The bar thingy she's leaning on could use some more shadowing
on it. She should have a shadow on it as well since she's leaning on it
and hovering.

Nice job overall, hope this advice helps for next time.