its ok for a begginer, now, here are the problems..
Its to squary try to imagine its a real life island are they shape squared?
try to make it look real, also i would put instead of that light blue water the normal one connected with the sand..
You should add some small stones, mayb some grass tuffs
Behing the "bridge", put some pillars wich are in doodad architecture, or some wood ones wich are in raw, archtitechture.. try to put stones, debris, brown rubble in dirt sand rubble¿ in sand
and most important, keep practicing and look at other people's islands or jungles and see whats the format so you can improve..
hope this helps biatch xD