first,you need a better background,putting a sun/moon doodad in the sky would make it better, you could also do a cliff with trees on it in a very far plan,
Second you have to organize the way you place the tiles:
Leaves under trees,dirt/rough dirst under rocks
for cliffs, use the rock tile with vines and lots of dirt
near shores use rough dirt then dirst
for all the rest, use lumpy grass and grass
