How to do realistic grass?
The grass looks great.
Clouds - To flat
Water - To blue, Maybe a little fog?..
One thing to remember, there are always different varities of grass, and flowers that decorate a landscape. Never be limited, imagine! It’s your BEST excercise!
http://www.blenderguru.com/the-secret-to-creating-realistic-grass/
in the future, use google before posting…
you have no taste in clothing, and you’re kind of ugly - HA HA HA - I couldn’t resist, you needed criticism 
Nice looking render, but ya, the clouds are funky looking more so than the grass (which is quite nice actually)
the grass looks pretty good maybe add a little yellow at the very tips and a little darker at the base… apart from that… ye the background doesnt look that good but u were asking about the grass so there u go hope it helps