
I'm giving a couple of ideas a try on an edit ...
1. the grass could be more interesting if leaving a bigger shadow on the "dirt"
2. the initial colour for the background did a nice job. It doesn't need changes imho
3. whatever the colour of the background, blue water seems nicer and definitely more "island" than greyish
4. having the grass going a bit further than the dirt might be nice too
5. "stroking" the edge of the "dirt" couldn't be bad (especially it would help thinking that the water is constraint between the two parts), but i'm not sure i did it right...
imho, the palmtrees are much more interesting this newer way, though i wonder if you could make all the leaves attached to the center of the trunk
I'd love to see a coconut with that style ... and imho the clouds have not found their definitive look .
Anyway, great job. I love it.