same story here as well .. I found Phil and Carol Carpenter's 'Marketing yourself to top mba programmes' good too .. especially the personal evaluation section .. I spent a lot of time evaluating myself with the questions asked in this book, which helped me a lot in my essays .. the sample essays in montauk's book give a fair idea of what sort of answers accepted applicants give to essay questions .. but, of course, dont copy anything from these samples .. it will be too obvious ..
also get somebody to critique your essays .. I got mine reviewed by friends and family which helped me a lot .. ask them to seriously review the essays though .. 'yeah the essays look real good, you should be admitted ..' kinda comments give you confidence but the critics help improve the essays more.
and try not to keep the essays till the end .. start before the gmat at least with a rough draft .. and continue refining them till the end .. I have been guilty of doing this .. I kept pushing mine till the end .. I had done my personal evaluation but hadnt drafted the essays till a couple of weeks before the deadline .. and ended up submitting my app at 11:55 pm on the day of the deadline!