Nice choice of subject, and it matches the brief perfectly.
However, the lillies are virtually lost in a "sea" of sameness.
There's not enough shadow-midtone-highlight or colour differentiation to make them REALLY stand out in your picture.
And then there are the foreign blotches of white on the lillies...
Nice colors and curves, and almost enough DOF. Focus more toward foreground would help some, probably needs something out of the plane of the water to spice it up.