Hmm... Detailing with Grass should be used in small clumps scattred all over. Use bushes, diffrent grasses, flowers, swamp, fences, kupols, etc... to add extra detail, but not too too much. The dirt can have 4 diffrent tiles in it, and 2 diffrent rock tiles. The rocks should be scattred, not so many
You also have too much detial in water.