I started out with your grass, and since it looked mostly like green flat stones with shading, I started by removing all of the dark 'blobs'. Then I jagged the edges of all the bright blobs, to give it the structure of being grass. This in itself also somehow works as a form of dithering, giving form and smoothing it all out at the same time. Then I started using the dark green to define places where the grass is deep, or at least that's what the brain is being tricked into believing. You can see that I did not at all care to see so that the grass could be tileable so that'd have to be fixed if I made a game sprite for real.
The trick with the dark green was that I almost never added it so that a dark pixel (almost) never touches a bright pixel horizontally or vertically // Edit: Or rather, that a whole dark strand of grass never is directly, in its entirety, touching a field of bright grass pixel-by-pixel, since that creates contrast > which makes the brain look for special detail > since there is none, it just comes off as grainy and distracting :<
So one wants to avoid that.
Then I simply played with the colours (Graphics Gale makes that go so damned fast.) until I found a low-contrast pallette of greens that looked smooth.
As you see, I went about it with a couple of different approaches; The middle is just a bright blob with jagged edges and some middle-bright-green pixels in there to create form and texture (I had my eyes pinned on the Preview window as to check that none of the middle-value pixels inside the bright blob came out as distracting; Diagonal placement of neighboring pixels come out as thin and smooth, I realized.).
The upper middle consists of more separated blobs, still with very little of the dark added in (it's so distracting when it's just everywhere, I think.).
The upper left was me playing around with the dark colours, came out half-okay I guess.
The right border was mostly me jagging the edges of your blobs. Half-assedly. (a beautiful adverb, that) :\
The lower left is still untouched.
Does that help? :]
Your avatar is über-nice too, I love the hi-res smoothness going on.