While graduate, law, and medical schools tend to request just one or two rather long essays, college and business school applications generally include several questions with more restrictive word limits.  Though more prompts may require more brainstorming, they usually make for easier writing and editing.  Indeed, you should consider this sort of application a welcome opportunity to tell the admissions committee about all the different qualities and activities that make you who you are.  Rather than stuff everything into one essay, carefully inserting transitions to craft a cohesive structure, you can expound on a variety of topics whose principal common feature is you.

This is not to say, however, that your essays need not relate to one another at all. To the contrary, you must consider the admissions officer's probable response to your essay set as a whole.  If it seems that you spent more time on your "extracurricular interests" essay than you did on your "intellectual passions" essay, the admissions officer is likely to infer that you prefer involvement in student groups over academic coursework.  To look at an extreme case, a student could conceivably write about the same activity for an "extracurricular interests" essay, a "most significant accomplishment" essay, and a "role model or influence" essay—but such a student would run the risk of presenting her interests as excessively narrow.  It is important to strike a series of balances in your essay set: between academics and extracurriculars, between intellect and personality, between creative and traditional structure, and so on.

A common mistake that many applicants make is to assume that a 100-word essay is less important than a 250- or 500-word essay and accordingly give it less attention.  Always remember that admissions officers are using the essays to get an overall picture of the applicant, and you must put effort into every brushstroke to make that portrait as compelling as it can be.  For instance, rather than quickly writing 100 words on a subject (which would take less than an hour), spend a bit more time crafting a 250-word essay on it.  Then, you can choose only the most effective parts of that longer piece to include in a shorter, denser version of the essay.

Finally, remember that the admissions officer is looking for analysis, not simply description.  Even if the question seems to prompt you for a straightforward story (for instance, "Tell us about your most significant non-academic accomplishment."), the essay should go beyond a simple narrative of the event, including at least a sentence or two about why it was so important and how it has affected you. 

For an example of a short essay set, click here.