1. Make your water completely still, or you'll keep these grainy reflections, which distract. Maybe just a tiny patch of wind somewhere (blend in a small sized perlin, by patchy perlin before the water shader).
2. Use shorter and more varieties of grass, and lessen the effect of rotation with slope.
3. Use more varieties of birch, this is very uniform. Perhaps leave the leaves on some of them, or some remaining leaves, thinned out if you will.
4. Try to break the very straight horizon, perhaps by a large rock or outcrop, or bunch of bushes.