Could you improve my writing?

Hello. Please do try and help me improve my school essay! Having read through what I have written, I believe that of the words I have used are 'placeholders' so to speak, and could be replaced with more effective ones. The tenses I have used are, I believe, muddled and do need fixing. Thank you

Elysnai, sitting staidly atop a boat, lamented poetry of beauty, form and aesthetics to her mother, Stealia, who being thrice her age, would have listened to her ponderings, had she not been vexed by the facets of her own lissom body she could see as reflections in the brass coils of her umbrella under which she lay. The boat had been adrift in the open water for what seemed an eternity until it began encroaching on the shadow of a weeping willow tree, whose panoply of leaves and branches when discerned from the eyes of Stealia, entangled with the accumulating clouds above. A truly wonderful wedlock between nature’s fecundity and Elysnai's lucidity would have come into being if she had freed herself from her mother’s pied poetry, and frolicked amid the canvas of art all around. As the boat encroached towards a shallow ridge of rocks, her awareness of this had been stymied by Stealia, who pondered the facets of her beauty.

Clandestinely, she commanded Elysnai to lament her favourite poem, only, on looking up, she was gone, and the view in which her lithe body could be seen had been replaced with one in which a few scraggly branches from the willow tree were knotted amid bracken, heather and other such visual froth. In an attempt to see where Elysnai had gone, she flung herself forward such that she mirrored the former staid posture of her daughter. The passage of time through which this occurred, as it were, was almost fettered to a point of inertia, and the forthcoming image she will now see of her daughter ought to have admonished the antecedent almost so as to be the source of nightmares for every pious mother.

On looking down at the lake, she is able to distinguish her daughter through the frothing and bubbling water beyond which her anguished face and writhing body are descending into the black abyss below, and at which point, the shroud shrouding Stealia's stoic temperament is lifted and her malign narcissism revealed. As when the water calms, her own reflection becomes visible, saturating her daughter’s; to which her terror quickly evaporates into wonderment at the sight of her divine beauty. She raises her hand to her face and touches her cheek, and on doing so, awakens from her nightmare.