Have you made your anti-aliasing yourself (because I can't see the colors in your palate)?
Besides how far are with Pixel Art/ Art in general?
Because it's hard to tell you how to improve if it's not clear what you know nor what you want to know.
If you are new to this entirely I recommend reading some tutorials or at least basic instructions.
If you already know a bit / much you should mention what you want to improve in, at least I can't tell by just seeing this.
Or maybe I'm just stupid here and don't get it and just wrote a senseless text ^^
But anyways I would love to help (if I'm able to) but like I said I don't know what you want.