The new guy likes Pokemon and stuff.

[X Gamer 66]

A few tips:

-Dithering sucks (in general, not specifically your dithering). It's very rare that you'll want to use it, even for textures. It just makes sprites look grainy.
-Try using a lot more contrast between your shades. Also, a pinch of hue shift usually helps. It's tricky to find shades that contrast but still blend, but they usually look better.
-Don't force extra color in when you don't need it. For example, that Dedede would be fine with two shades of blue.
-Generally, you should try using more vibrant colors. When you're changing shades, don't just add black and white, add tiny pinches of yellow or blue respectively. Be bold. Dull colors are boring.
-I like to think of selout (selective outlining) as "shading the outline". Basically the idea is to create a lighter outline where the lightsource hits. The Larvitar in your av has the right idea going.
-Smooth out your outlines with anti-aliasing.
-As others have said, don't force the details in there if it's too cluttered. Let the details be implied.

And I must say, you've got pretty good outlines for a beginner. Keep up the good stuff and whatnot.