1.The colors are bland and don't make for that nice-of viewing...you need contrast, contrast! The colors in the first piece need contrast...BAD. And yet, they also Hue-shift waaay too hard to look pleasing together..Purple -> Read- >orange, all in just three colors...
this isn't going to work on small pieces where you NEED as much readability as possible, people should be able to see it decently without ever having to zoom-in on it.
2.As for dithering on such small pieces...This is just painful. I wouldn't, just use another color, it won't hurt at all...Just don't use like >30 colors...use around 10-20. Why would you dither small pieces, anyway? Dithering only works on large pieces where you can't see the dithering taking place too much and it acts like an additional color(s). On small pieces dithering just looks like a grid, this is not what you want.
3.Anti-alas your lines by either applying:
applying a lighter color inside the outline it's-self at the exact jaggy pixels
or apply a color thats between the inside color (let's say green) and line color (let's say real dark green) and apply on the inside of solid shapes next to jagged steps...
Linky-
http://www.spriteart.com/tutorials/01_AA.html4. Why black outlines? Real life doesn't have black outlines...To me, this is just ugly. I can understand black-outlines for contrast against backgrounds and such in games, but even then.
5. Please, don't double-post, the admins will hit you with a stick...If you get no replies, this means:
A. People have taken a glance, but are too busy to reply.
B. People are in the process of typing or editing a piece for you.
C. You've got bad luck and just need to wait it out.
Good luck, I hope this has helped.