You terrain textures are really low res. Maybe increase the tiling? Try using the conform to terrain normal tool for your vegetation. You have foliage growing out of vertical rock which you can fix with the angle masking tool under vegetation. The water doesn't really fit the scene, especially in the pool area, fiddle around with this kind of stuff in the Time of day and environment tab.
As it stands I can't really tell what style your going after, its kind of a wash.