This part right here is to long:
Please bear that in mind, because I feel that I need to inform you that I have a cluttered desk. ----those two phrases I crossed out seem wrong in a few ways. Addressing the reader directly "please bear in mind" creates a certain kind of presumptuous atmosphere in the essay... and "I feel the need to inform you" is like, "cliche" or something...
My desk frequently houses empty water bottles.
Some readers frown on the use of water bottles for environmental reasons like the concern you mention. I guess I think there is a better way to say this... like... instead of "my desk frequently houses empty bottles," you can write, "I have had the same two water bottles on my desk for a long time, because I never get around to recycling them, but I do not want to resort to just throwing them away."
And with the nail polishing part... I think... I think with this whole essay you had not established a purpose before writing. Or maybe your purpose was just to express yourself, but I think your purpose should be to show them a glimpse of a person who has excellent clarity and self-discipline, someone who deserves admission and will really do excellent, meaningful things.
:-)