I would add some white/sea foam. Try making the water more flat so it looks flat instead of a wave. Try adding texture and more shadows into the sand. With the face make the eyes more squinted cause of the sun. Add bronze instead of purple shadows. And id make the hair behind them in larger clumps. (You font need to do any of this. Its just what i would try.)
#Tips on composition
crisp saffron
sullen palm
Did you take a good look into the direction that the overall lighting follows? Because the shadow behind the character needs to be consistent (direction-wise) with the shadows on the character’s head as well as the shadows on the clothes.