I probably sound like a jerk saying this, but if you want to make tilesets you need to get at least a basic grasp on pixel art. Seven lines and a flood fill of gray does not a rock make.
I'd also suggest using something other than MS Paint; you get to use proper transparency, and it will probably speed things up in the long run.
If you're looking to improve with your KS tileset-drawing abilities, I recommend studying Nifflas' tilesets, especially those in A Strange Dream.