Not to be rude, but, it's supposed to be a spaceship, right?
It'd help to have more information about what you're trying to achieve and what the sprite is supposed to be for, and maybe what there is about the sprite that you're unhappy with.
I think that you need to make the purple shade darker, to better contrast the light blue, which I am interpreting as glass, for a cockpit and windows.
You seem to be using a lot of pillow-shading in your sprite. You should try to find a lightsource, and stick with that. You'll come up with a better defined shape if you do that.
This is a really good tutorial on how to shade when doing pixel art. That might help you some.
Another tutorial, which relates less directly to your current piece, but is pretty much required reading for any new pixel artists, is
this.
I really hope I'm not coming across harshly. I'm not trying to make you feel bad about your artwork or anything. For your first foray into pixel art, this is really not bad at all. You should see the first sprite I made. Uck. Keep at it, and you'll get good, I promise.
