"Compelling" Personal Statement?

I am hoping to be accepted into Case Western Reserve University's Pre-Scholars Program. Along with an application that I need to fill out, I am required to write a one page Personal Statement. Problem is, CWRU will only accept 15 students out of all the high-schoolers who apply. Aside from my past schooling, which is too late to change, the only factor I have in my favor will be an outstanding Statement. The only help I've gotten from the CWRU office is that the Statement should be "Compelling". So I wonder: How can I write a truly compelling Personal Statement to set myself apart as one of the 15 who should be accepted?? I want to be part of this program more than anything, so I'll appreciate any help you can give me! Thanks in advance.