milias
Man, the Wharton essays are long! 750-1000 words? That's like a book!
As a Lauder applicant you must write 6 essays for a total of 5,000 words. What was especially challenging for me, was writing 2,000 words for "why Wharton?" and "Why Lauder?" without allowing for too much overlap or just writing for writing's sake.
Time allowing, it is better to work on the essays and then take a break for a few days. You might find yourself reading a book or washing your teeth when suddenly you have that "aha!" moment that brings with it a relevant anecdote from your past or the words you've been searching for to convey an idea.
I guess the conclusion is that applying to b-school is hard, sometimes frustratingly so...