Hey man, welcome to Pixelation.
Well, you have an excellent jumping off point here, there are just a few points that need some attention.
Firstly, your scene is lacking shading; it's making everything look flat and dull.
Secondly, the "coastal" tiles are in a different perspective than the rest of your scene, it gives the perception that the world is "bending" at the sea and at the pond.
Finally, The grass seems a little boring, try developing some tiles which have a little more movement rather than just a single color.
Good work so far man, with a little polish you'll have a nice scene here.