I've spent the past several months helping others edit their essays for several schools. It's a fairly tedious process that involves you writing some stuff and sending it to me, me reading it and leaving red marks all over before sending it back to you - repeated maybe 15 - 20 times.
To make it easier for you to write an essays, let's go through the basic requirements of a good essay.
1. You need, inspiration - lots and lots of it. There are several ways you can get it, but the best way is to get some whiskey and start drinking. Actually, drink on the night that you're planning to write your essay. While you're sober, start jotting down little stories that would look like the following the next morning
Rescued a village - dug waterholes - ate Mcdonald's
Top of class - biggest geek in class - had no friends
and so on... actually, when you feel guilty the next day, you'll probably rewrite everything. But yes, write down little anecdotes of your life. Compile maybe 20 - 30 stories for various situations, this is your story bank.
2. Look at the essay questions and look at your story bank, mix and match till you feel it's pretty good. Then start to write the story with sufficient detail, the trick is too much detail and it's boring and long, too little details and it'll be boring and superficial - you need just enough detail to get the reader's attention while enough to explain what happened. It's not easy, so you'll probably have to do it for quite a while.
At this point, you can start to stretch your stories a little bit. You work in credit sales? Rewrite it to say that you were the top sales person in personal loans. You get the idea, a little bit of exaggaration is ok.
3. Decide on whether your essay answers the question. Write it to answer the question. If it doesn't answer the question, then it's a lousy essay with an interesting story.
It'll probably take you a while to get used to this, do it a few times for your application. At some point you'll hit the zone and just be able to write flawlessly on why you need an MBA while talking about how you saved your company from going bankrupt...