Let's see if I can communicate about the perspective of the island and water without the use of hand
gestures.
Regarding the shoreline:
I'm guessing you're trying to portray a small inlet or cove with that slight arch of blue against the green?
(On the left.) In that case, you don't need to actually arch the blue; doing so gives the impression of a rolling
wave. Combined with the off-kilter white lines which I thiiink are depicting breaking waves, it looks like there's
a small waterfall in front of the larger building. Unless that's what you were trying to depict?
Your major problem is that you want to curve lines (like the breaking waves or shorelines) because your mind knows that
when viewed from above, you would see a curve; however, from the side, those "curves" look rather flat. I
suggest you look at photos of Caribbean islands; the water is brilliant enough that the breakers and beaches show up in
high contrast.
Example Image
1: Note how the shoreline of the island looks flat, just somewhat jagged.
Example Image 2: Note how the
farthest edge of the breakers is almost totally horizontal.
And so on. Hope this helps!